Abstract Traditional product costing systems have become increasingly irrelevant in the present day multi-product manufacturing environment with processing facilities which incur a much larger proportion of their costs in overheads than in direct labor. For example, specialty products which may have similar direct labor requirements as standard products but impose more overheads will bear less cost than they impose given the application of overheads based on direct labor. It has been suggested in the recent literature that activity costing systems which trace overhead costs to different activities and then apply costs to products based on the demands made by that product line on these activity centers correct this problem. Activity costing requires overhead costs to be traced to these activities. However, there are some costs such as the cost of delay in common processing centers and the holding cost of work in process inventory which are difficult to trace to activity centers. In addition, specialty products impose such costs on other products and therefore, in the application process, these externality costs have to be traced back to the former. This paper suggests an extension of the current activity costing framework and uses results from queuing theory to incorporate these costs. It also illustrates the application with a numerical example and a real life case study.
Bill Srinidhi (Tue,) studied this question.