Use of Variators in Applying the Cost Calculation Methodology in Small and Medium Furniture Enterprises Based on Changes in Human Body Dimensions

Based on the research of anthropometric measures of Slovak adult population, it can be observed that during the last 25 years, anthropometric data have been rising by about 4.5-5 % in most analysed characters. As data on human body dimensions changes, the requirements for material consumption and production time, expressed by the rate of labour cost, are changing. In this context, sustainable profi tability of the company can be achieved through each segment of a value chain. One of these segments is the product and its price, which is based on costs allocated in the system of full or variable costing. As the value of quantiles characteristics of anthropometric characters was used to create ergonomic, health and construction norms and standards in the furniture industry, it is necessary to review the adequacy of existing standard-size single bed. Since the dimensions of single bed are standardised, 200 cm x 90 cm or 200 cm x 100 cm, it is clear that due to the secular trend of anthropometric measure of a man, the dimensions are currently inadequate. This paper presents the use of variators when applying the most commonly used absorption costing in small and medium furniture enterprises. It shows the costs involved, when the input parameters are changed.


INTRODUCTION 1. UVOD
Small and medium-sized enterprises (SMEs) represent a signifi cant part of the economy and industrial system of every country (Buehlmann et al., 2013;Bumgardner et al., 2011).In the European Union, as well as in the Slovak Republic, SMEs represent more than 99 % of the total number of business entities (Slovak Business Agency, 2016).Globalization is putting the pressure on furniture SMEs to achieve innovation and modernization of technological and manufacturing processes (Barčić et al., 2016;Tokarčíková and Kucharčíková, 2015).
In order to be successful in the market and to increase the competitiveness, the main role of the company is to come up with product innovations.An economic aspect is another non-negligible challenge, too.When designing housing, it is necessary to consider the basic biological needs of humans, the quality of the environment, as well as microclimatic, acoustic, optical and environmental hygiene.Therefore, it is essential to take into account the dimensions of the human body and the resulting spatial needs necessary for the performance of housing-related activities.Spatial needs and parameters for performing activities in the apartment are derived from the average body dimensions of people.However, when identifying a particular client, it is necessary to take into account his/her individual needs.Changing anthropometric parameters of a person are associated with the development and growth of generations -the secular trend.It means the change in physical dimensions between the past and present generations at the same age range.These changes do not occur suddenly but over a long-term development in one and the same territory.It is the result of improving health care, increasing the quantity, quality and availability of food, mixing ethnicity and peoples, various psychosocial changes.The secular trend is best observed when considering the human body height.Based on previous fi ndings, it can be stated that secular trend was, on average, confi rmed by 1.55 mm per year (Sedmák and Hitka, 2007).
The bed is the basic object of residential equipment.High quality demands are placed on bedding furniture.People spend a third of their life on it.From the point of view of anthropometry, physiology and hygiene, the size of the bed must be suitable for the human body taking into account the fact that the body position changes during sleep.From the anthropometric point of view, the length, width and height of the bed area is particularly important (Hitka and Hajduková, 2013; Kotradyová and Kaliňáková, 2014).
The production of furniture specifi c for residential space is an issue that humanity has been dealing with since prehistoric times.Primitive people created various primitive tools.Even in this activity, a man needed to sit comfortably.In ancient Egyptian times, people already thought about the way how to adapt furniture to man and his needs.A seat with a slightly inclined backrest was made for a more comfortable seating in ancient Egypt times.At the same time, the fi rst stool was made in the form that is still used nowadays.The Rococo period, called as the style of the interior, brought other revolutionary changes.People were looking for ways how to sit comfortably for hours without pain.Gradually, serial furniture production was introduced because production was not economic.During the 2nd World War, it was possible to buy modern furniture with ergonomic shaping (Peteri, 2017;Kolena and Vodráková, 2013).
In Europe, Scandinavia has become the best country in the whole furniture production market, perhaps because the country was not hit by the war as much as most other European countries.Designers adapted to new knowledge in the fi eld of sociology.Slowly, the fi rst housing developments were built, requiring furniture to be adapted.At that time, everyone could buy furniture, especially because of large-scale production.It was not necessary to use inherited furniture.Thanks to this phenomenon, every family could change the furniture several times.On the other hand, the furniture was not of high quality.Later, aesthetic and emotional aspects have begun to be added.Seating furniture had becoming more and more suited to the human body (Veselovský and Kotradyová, 2009).Based on these trends, the furniture began to be broken down according to the activity it was used for.During the past decade, ergonomic research focused especially on the design of work furniture based on the biomechanics of the human body.Many researchers dealt with the principles for the design of chairs and desks in SAŽETAK • Na temelju istraživanja antropometrijskih mjera slovačke populacije odraslih možemo primijetiti da su se u posljednjih 25 godina antropometrijski podatci o većini analiziranih značajki povećali oko 4,5 -5 %.Kako su se mijenjale dimenzije ljudskog tijela, tako se mijenjala i potrošnja materijala te vrijeme proizvodnje, što je izraženo udjelom troškova rada.U tom kontekstu održiva se profi tabilnost tvrtke može postići putem svakog dijela lanca vrijednosti.Dio lanca vrijednosti čine proizvod i njegova cijena, koja se temelji na troškovima dodijeljenima u sustavu potpunih ili varijabilnih troškova.Budući da je vrijednost kvantitativnih antropometrijskih značajki iskorištena pri izradi ergonomskih, zdravstvenih i konstrukcijskih normi u industriji namještaja, potrebno je razmotriti adekvatnost dimenzija postojećega standardnog kreveta.S obzirom na to da su standardizirane dimenzije kreveta za jednu osobu 200 cm x 90 cm ili 200 cm x 100 cm, jasno je da zbog sekularnog trenda čovjekovih antropometrijskih mjera današnje mjere standardnog kreveta više nisu adekvatne.U članku se prikazuje primjena varijatora u najčešće korištenim metodama ukupnih troškova u malim i srednjim poduzećima za proizvodnju namještaja.Također se prikazuju troškovi pri promjeni ulaznih parametara.
Ključne riječi: inovacija, izračun, kreveti, varijator, mala i srednja poduzeća ...Potkány, Hitka, Lorincová, Krajčírová, Štarchoň: Use of Variators in Applying the Cost ... the workplace, particularly for computer system users (Burgess-Limerick et al., 1999;Cook and Kothiyal, 1998;Aaras et al., 1997;Villanueva et al., 1996;Kumar, 1994;Naqvi, 1994).In the fi eld of interior and furniture design, comfort was based on correct dimensions of the user or group of users.Over the last millennium, man was physically developing.This is indicated by the skull, denture, and post-skeletal skeleton, decreasing body weight and brain capacity.Changes in furniture dimensions are visible in the history of architecture and furniture development, too (varying the height of holes, ceilings, etc.).Since the Neolithic period, Europeans are still subject to the conformationalheterogeneous trend (Kolena and Vodráková, 2013).This trend is manifested by different features of the body, which are being simulated by Europeans.It is well known that the environment has a signifi cant impact on these changes.Therefore, planners, designers and engineers should be aware of the space occupied by a person in different positions, and they should provide safety for movement and relaxation (Smardzewski, 2009).
Body dimensions, such as average body height, vary and develop in time (in comparison with the past, body dimensions are greater) (Ozer, 2007;Carrascosa et al., 2004;Malina et al., 2004;Krawczynski et al., 2003).For example, the length of the bed has increased considerably since the Middle Ages.In addition to the increase in body height and weight, the differences in geographic segmentation increased, too.Nowadays in Europe, dimensional standards applicable to architecture and furniture industry cannot be unifi ed because of signifi cant differences in the population, especially between Southern, Northern and Central European regions.The European Union's attempt to introduce uniform dimensional standards has proven to be unrealistic.The market hits the conservatism of society as a whole.Reactions to these facts are very slow.It can be seen in sectors where consumption is a major economic factor, for example the automotive industry, aerospace industry, textile industry and shoe industry (Woolliscroft et al., 2015).
In literary sources, the structure of calculation formula can be found (Lazar, 2012;Poniščiaková, 2010;Popesko, 2009).It is the so called general calculation formula as the starting basis for calculation formulas for different conditions (Hradecký et al., 2008).The general calculation formula includes direct and indirect (overhead) costs.Overhead costs represent a signifi cant part of total costs (Synek et al., 2007).Therefore, it is important to manage them and to defi ne their roles so as to reduce them.Costs contribute to the economic growth, because costs are one of the main sources of its reduction.For practical management of costs, it is necessary to implement the classifi cation of costs.It is necessary to consider the type of production, technology used, organization of internal departments.The general calculation formula is used in the methodology of absorption calculation.The absorption calculation implies a number of limitations (Popesko, 2009).These limitations are based on increasing inaccuracies, caused by disproportionate cost allocation.According to the author, this uncertainty is deepening in the context of historical changes in the share and structure of overhead cost.
The problematic factor is still the allocation of overhead costs.Variators can be used for the process of planning overhead costs (Synek et al., 2007).The values give information on the percentage of costs increase, if performance or other value is increased by 1 %.They are determined as the share of variable costs in the total overhead costs as a relevant share of the specifi c group of overhead costs.This share reaches values in the range from zero, when all costs are fi xed, eventually to one, where all costs can be considered as variable items.Thus the zero variator is the item of centre budget and its costs are total fi xed costs in relation to its activity (Hradecký et al., 2008).On the other hand, a variator equal to one determines costs that grow proportionally with the change of the centre size activity.The variator can be expressed as "centesimal", "decimal", and sometimes even as "unit" (Lazar, 2012).
Since man is considered the scale of all things, its physical dimensions are used as the basis for all measurements.The physical dimensions are very important because small changes can have a considerable impact on health, safety, and productivity (Mokdad, 2002).The last and still used anthropometric database of our population comes from the times of Czechoslovakia.Nowadays, most of the norms and standards are based on data measured before 1955, and therefore workplace parameters are inappropriate (Kovařík, 2009;Cvičelová et al., 2005).Norms and standards are outdated and, moreover, physical dimensions of each new generation are higher than those of their ancestors.The increase is signifi cant in the long term.In general, as the statistics show, young men are higher than their fathers by about 4.5 cm, and higher than their grandfathers up to 7.5 cm (Kolena and Vodráková, 2013; Sedmák and Hitka, 2007).
The literature presents (Taifa and Desai, 2017; Kovařík, 2009; Mokdad, Al-Ansari, 2009; Smardzewski, 2009; Malina et al., 2004;Krawczynski et al., 2003) different approaches how to establish the basic parameters of furniture, i.e. how to determine the optimal length, width and height of single bed area from the perspective of anthropometry and ergonomics, as designing of standard furniture needs direct involvement of anthropometric measurements.In our case, we took into account the development forecast of the anthropometric dimensions of population based on the secular trend.It is possible to create a universal design by adding the standard deviations (suitable for almost the entire population).Such an approach ensures the production of furniture with dimensions suitable for present and next generation.
The furniture price is closely related to two conditions -the recoverability of the furniture material, and the energy intensity of its processing.Wood is the most frequently used material (Dušak et  completely renewable resource with low power demands in processing and with easily disposable waste.Wood as a material can be used in furniture manufacturing due to its unique harmony of its aesthetic and technical-technological properties, easy workability and strength. If a company wishes to be effi cient and successful in a constantly changing environment, understanding the buying behaviour of consumers is crucial for the company.Consequently, companies producing bed furniture must modify their calculation methods of pricing to be able to forecast their fi nancial situation in those areas, expressing causal relation between the costs and respective performance (Barroso et al., 2005).Companies are subject to great competitive pressure.Offer exceeds demand in many areas, so it is important to focus on satisfying customer needs.The company needs to look for cost reduction option.Companies can only be competitive in the current dynamic environment by focusing on the future and not just on surveying the past.
Calculation formula represents the list of different types of costs that should be completed with a method of quantifi cation of these items in relation to the calculated performance (Popesko, 2009).It is diffi cult to defi ne the universal calculation formula for all products, because the enterprises compile calculation formula adapted to their own specifi c conditions (Macík, 2008).
The main task of SMEs is to innovate the products and to prepare new types of beds that can be used by large businesses in the future.The aim of this paper is to present the use of variators in the selected medium-size company engaged in furniture production when applying the most commonly used absorption costing in small and medium furniture enterprises.

MATERIJALI I METODE
The forecast values of the relevant body dimensions of adult population (Table 1) were used to optimise the single bed dimensions for the needs of the present and future population.The sampling unit was composed of Slovak adult population, i.e. population over the age of maturity in terms of the growth process of people, i.e. 18 years and more.A total of 3.358 students from Slovak universities were involved.The sampling unit covered the population of the whole Slovak territory, which increases its representativeness.The technique of direct survey was used to acquire the empirical data.Data were collected by measurements of selected anthropometric characters (height, shoulder width).
Based on the fi ndings of statistical properties of body dimensions of the current Slovak population, it was possible to determine the dimensions of a single bed corresponding to the population.The overall design of the single bed is given in Figure 1.
Body height of men (BH m ) was used as the factor necessary to determine the dimensions, mainly the length of the lying surface.Comfortable sleep must be provided; therefore, comfort factor (CF) was added.Then the total length of the lying surface (LS) was calculated as follows (Prokopec, 1998): By summing the data stated in Eq. 1, it was possible to calculate the length of the single bed suitable for family house.Shoulder width (SW) was crucial for determining the minimum width of the lying area (b 1 ).It was necessary to enlarge the shoulder width by 50 %, and then two standard deviations were added due to trend development of population growth (Eq.2).b 1 = 1.5 SW+2s x +0.25 (1.5SW+2s The fi nal length of the lying surface was calculated as 230.5 cm.The fi nal width of the lying surface was calculated as 102.3 cm and the fi nal single bed height was calculated as 45.7 cm.When analysing the dimensional characteristics of the current male Slovak population, it can be clearly stated that there is a positive secular trend.A body height increase of +4.5 % was recorded.In absolute terms, it represents an average increase of +8 cm.A similar development was observed in the arms width.The parameter increased by up to 6.7 %.It represents an increase of +3 cm.This might be the result of better nutrition, better psychosocial factors and socio-economic conditions of today's population (Sedmák and Hitka, 2007).
According to the author, this variator determines the degree of dependency of overhead costs spent on specifi c relative value.The relation for the determination of variation is as follow (Hradecký et al., 2008): Where V -variator, 1 -budgeted period, 0 -initial period, OC -overhead costs, AB -allocation base.
Eq. 3 and Eq. 4 were used for the determination of individual items of overheads variators.
The starting point for price determination of single bed was a general costing formula.For the determination of direct costs of the product, we started from the consumption standards and time standards.Direct material consumption standard was supported by the technical documentation.Direct material consumption was set at 4.39 m 2 for original bed dimensions of 200 cm x 90 cm.As a consequence of bed dimension increase to 230.5 cm x 102.3 cm, consumption is increased to 7.17 m 2 .Unit acquisition price was planned at the level of 3.69 €/m 2 .By multiplying these two factors, the amount of material consumption was quantifi ed in value terms.The level of direct wages was determined through time consumption standards.The values were set by the enterprise in the amount of 3.20 € based on the actual need of 0.661 standard hour (SH) per product.For the innovated product, with increased dimensions, the time consumption standards changed to the level of 0.85 SH/ product.The item of other direct costs (including the necessary number of connecting pins, cover caps and subsidiary material) remained unchanged.
In our case study, different allocation bases were used, so we were working with differentiated direct costing.Since all the costs were included in the calculation formula, it was the absorption costing (Poniščiaková, 2010).

REZULTATI I RASPRAVA
Secular change seems to be a major characteristic of body physique of people in almost all countries of the world (Mokdad and Al-Ansari, 2009).Secular change was confi rmed in Algeria, Australia, Cook Island, Hong Kong, India, Japan, Mexico, Poland, Spain, Turkey (Ozer, 2007;Carrascosa et al., 2004;Malina et al., 2004;Krawczynski et al., 2003 1992).Secular trend was proved by the anthropometric survey conducted in Singapore and Indonesia, too.According to the research, the average male fi gure grew by 5 cm in the last 19 years and the female by 6.9 cm.These results are similar to other research (Mokdad and Al-Ansari, 2009).The results of anthropometric survey carried out on a sample of male and female Bahraini school children aged 6-12 years show a gradual increase from age 6 to age 12 in all body dimensions.Nutrition factors, socio-economic status, urbanization, physical activity, climate and psychosocial deprivation have contributed the growth in the dimensions of people in Singapore and Indonesia (Chuan et al., 2010).Living standards and dietary habits caused the increase in the average physical dimensions of students (Jung, 2005).Based on researches, it can be stated that the positive secular trend has a global impact.
The infl uence of these impacts is presented in our research for assessing the changes in production of a specifi c type of furniture -single bed.Items of production overheads were divided into technological and general section.The overhead tariff of 3.50 €/SH was determined for the technological production overheads.The overhead rates were also determined for other overheads.For general production overheads, the value of direct wages was selected as allocation base.For supply overhead costs, the amount of direct costs was selected, while for administrative overheads and sales and distribution overhead costs, it was the amount of production costs.Table 2 presents the initial situation and the calculation per single bed after the increase of its dimensions.In this case, we consider that the values of overhead rates have remained unchanged, despite the change in consumption of direct (technological) material and direct (technological) wages.
We determined new overhead rates by using of the variator method.The fact that the fi xed part of the overheads remains unchanged and only the variable component of indirect costs changes was taken into account.
The variator value for supply overhead costs (SOC) was determined at the level of 68 %, in the general production overheads (GPO) at 43 % and at 37 % of the sales and distribution overhead costs (SDOC).Only fi xed costs represent the administrative overheads (AOC), and therefore the variator value is quantifi ed at the level of 0. Data on percentage increase, shown in Table 2, were used for this calculation.Changes in overheads volume after increase in bed dimensions were detected by the determination of increase in the cost components by the value of the variable component of relevant overheads and its percentage increase after the increase of dimensions.After level change recalculation of relevant overheads, these overheads were used for the determination of the new overhead rate.The original value of allocation base after dimension increase of single bed was used as the allocation base for the hypothetical production volume of 1.000 pieces.The determination of the current level of overhead rates on variator level is methodically determined as follows: Table 2 also presents the modifi ed calculation of initial and new dimensions after application of new overhead rates.
Based on fi ndings shown in Table 2, it can be concluded that, using of the traditional approach of compiling calculation, an increase of more than 52 % can be expected in total output costs after the increase in bed dimensions.While preserving the original level of 15 % profi t, there would be an increase in the sales price of the product to the level of 156.63 € excluding VAT (which is an enormous increase of 52.59 %).This enormous increase would be caused by absence of overhead rates updates and proportionality of costs of a fi xed nature in individual overheads items.
After the application of overhead rates determined by variators, the increase in total costs was about 21.92 % (Table 2).The same percent increase occurred in the sales price of single bed at the constant relative profi t level.More exact information on total product costs was obtained by applying the variator method in updating overhead rates.
With the increasing economic importance, customers are becoming increasingly demanding (Ma et al., 2017).These demands put pressure on businesses to establish innovations in their work, for example by outsourcing the maintenance operations for building equipment (David et al., 2017;Gilson et al., 2016).Factors such as price, performance, and design of the product are crucial for the customer when purchasing the product.Product safety and environmental impact have also become important criteria.The improvement of the customer satisfaction level is conducive to meeting customers' demands (Zheng et al., 2017).Accountability to customers in this area can be expanded in providing good service at a fair price, in handling complaints, in undertaking the communication with the customer, etc.If the company wants to be successful in long term, business activities must be systematic, controlled and based on purposeful innovation.Through successful innovation, companies try to get an important and long-term sustainable competitive advantage.In this context, sustainable profi tability can be achieved through each segment of a value chain.One of these segments is the product and its price.
Compared to previous calculations, the difference is more than 27 € in favour of lower product price.Thus determined price is more acceptable for customers in terms of marketing principles.However, it still needs to be taken into consideration that the methodology of absorption costing was used, while it would be necessary to determine the overhead rates of individual groups also in the context of the complete product portfolio information.The most ideal solution is to use price decision-making principles of variable costing.This calculation is only made with the variable costs, where the most important element in comparing the effi ciency of products is the level of contribution margin (difference between price and variable costs of product) (Synek et al., 2007).This calculation considers fi xed costs as items, which are essential for ensuring the business operation in a particular period.These costs are subsequently added to the economic result for the whole period (by deduction from the total level of contribution margin).According to the author, variable costing is based on the assumption of fi xed costs stability.By the calculation based on the cost breakdown to fi xed and variable components, the knowledge of costs level can be achieved by performance unit and also evoked separately by other capacity scope decisions (Poniščiaková, 2010).In our case, the principle of variable costing was partially used.By the method of variators, the separation analysis of variable and fi xed overheads was carried out.By updated overhead rates, the effect of proportionality of fi xed costs was eliminated.Our aim was to eliminate undesirable inaccuracies caused by absolute and relative increase of fi xed capital due to differences in capacity utilization (Poniščiaková, 2010).

ZAKLJUČAK
Secular trend of anthropometric dimensions of the adult population of Slovakia resulted in the consideration of dimensional changes in bed furniture.Based on the results of the long-term research of anthropometric measurements of Slovak adult population, it can be stated that the observed variables have been rising by about 4.5-5 % during 25 years.Our research was further aimed at reconsidering these changes for standardised dimensions of a specifi c type of furniture -single bed.The dimensions we proposed are as follow (length = 230.5 cm; width = 102.3cm, and height = 45.7 cm).With the change of dimensions, it was necessary to consider the increase of the production costs.The required principle is the choice of the calculation technique, which would allocate an adequate part of the overhead costs to the innovative products respecting the changes in direct costs.The ideal solution would be the implementation of variable costing principles.However, in this paper we have presented the traditional system of absorption costing with the possibility of using the methods of variators.Although the problem of allocating the overhead variable costs could not be avoided, this method eliminates the effect of proportionality of fi xed costs.Our intention was to preserve the traditional and still preferred system of calcu-lations in the furniture companies in Slovakia.Using the variator method for each group of indirect costs in the areas of supply, production, sales, distribution, and administrative overhead, the change in direct costs (+11.17€) resulted in a change in overhead costs.Compared to the traditional absorption calculation, based on rate constancy, the minimum change in overhead costs (+8.4 €) was caused by eliminating the impact of the proportionality of fi xed costs.
The actual essence of innovation is the overheads rates update and monitoring of variator values.The essence of our proposal is to monitor overhead costs in the most detailed classifi cation with the determination of the appropriate types of allocation bases.These allocation bases should refl ect as accurately as possible the ratio of the change in overheads and the actual value of these bases.This dependence could be assessed using a correlation and regression analysis to determine the level of correlation coeffi cient.Correlation coeffi cient can be quantifi ed by comparing the past data of the variables, such as the specifi c groups of overhead costs, and the considered allocation bases.Certainly, the ideal solution would be the parallel use of variable costing system, which would require additional investments in information base change, software support and personnel training.We consider our solutions to be innovative in the area of application of the available calculation methods.