Process Costing Systems
6. Common Mistakes with Transferred-in Costs 7. Mention of sources used
The difference between job costing and process costing is the extent of averaging used to compute unit costs of product and services. The cost object in job costing is a job that constitutes a distinctly identifiable product or service. The quantity of manufacturing resources is different in any job. It would be incorrect to cost each job at the same average manufacturing cost. So, when like or similar units are mass produced, process costing averages manufacturing costs over all units produced.
The costs of a product are important for inventory calculations, pricing decisions and product profitability analysis. It's also important for measuring how well the management is done and if costs are reduced effectively.
The best way to show how process costing works, is by example:
Global Defense, Inc, manufactures thousands of components for missiles and military equipment. One of these is called DG-19. The product-costing system for DG-19 has a single direct-cost strategy (direct materials) and a single indirect-cost category (conversion costs). Each unit passes through two departments: the Assembly Department and the Testing Department. Every effort is made to make sure that all DG-19 products are identical. Direct materials are added at the beginning of the process in Assembly. Additional direct materials are added at the end of processing in the Testing Department. Conversion costs are added evenly during both processes. They include manufacturing labor, indirect materials, energy, plant depreciation and so on. After leaving the Testing Department, the DG-19 component is transferred to Finished Goods.
2.1 Case 1: Process Costing with no beginning or ending work - in - process inventory
During January, the first month of the period, Global Defense starts with the manufacturing process. All units will start and end in this period. Altogether, Global Defense will manufacture 400 units of DG-19 during this period.
Global Defense records direct materials and conversion costs in the Assembly Department as these costs are incurred. By averaging, the assembly cost per unit would be $ 56.000 / 400 units = $ 140:
Each unit is identical in this case, so we assume that all units receive the same amount of direct materials and conversion costs. The unit costs can be averaged by dividing total costs in a given accounting period by total units manufactured. This approach is for example used by banks to compute the unit costs of 100.000 similar customer deposits made in a month. It is usually used by organizations with mass production of standard units and no incomplete units after the period.
2.2 Case 2: Process costing with no beginning but an ending work - in - Process Inventory
There is no beginning inventory in February, because all 400 units produced in January had been fully completed. Due to customer delays in placing orders, it was only possible to produce 175 units in February.
The 225 partially assembled units as of February 28 were fully processed with respect to direct materials, because all direct materials in the Assembly Department are added at the beginning of the assembly process. Conversion costs are added evenly during the assembly process. Based on the work completed relative to the total work required to be done, an Assembly Department supervisor estimates that the partially assembled units were, on average, 60 % complete as to conversion costs.
Total costs for February:
Problem: How should Global Defense calculate the cost of fully assembled units and the cost of the partially assembled units still in process?
The following four steps help us to find the answer:
Step 1 tracks the physical unit of output. It shows, where they come from and how many units are there to account for, and where they go and how they are accounted for.
Step 2 measures the output in equivalent units, not in physical units, because not all units had been completed. The 400 units are complete in terms of equivalent units of direct materials, because all direct materials are added in the Assembly Department at the initial stage of the process. So you count all 400 units in equivalent direct costs.
The 175 fully assembled units are completely processed with respect to conversion costs. The partially assembled units in ending process are 60 % complete (on average). Therefore, the conversion costs in 225 partially assembled units is equivalent to conversion costs in 135 (60% of 225) fully assembled units. So, 310 equivalent units of conversion costs are assembled and transferred out and 135 equivalent units are in ending work - in - process inventory.
In step 3, equivalent unit costs are computed by dividing direct materials and conversion costs added during February by the related quantity of equivalent units of work done in February:
In Step 4, total costs to account for are summarized and assigned to units completed and transferred out and to units still in process at the end of February. Since the beginning balance of the work - in - process is zero, total costs to account for consist of the costs added during February: direct materials $ 32.000 and conversion costs $ 18.600.
Direct material costs are 225 times $80 (=$18.000) + Conversion costs: 135 times $60 (=$8.100). Total costs are therefore: $18.000 + $8.100 = $26.100.
2.3 Case 3: Process costing with both beginning and ending work - in - process inventory
In march, Global Defense has 225 partially assembled units in the Assembly Department. During march, Global Defense placed another 275 units into production.
Step 1 traces the physical units of production. In march, 400 units are completed and transferred out, 100units are in ending inventory.
Step 2 computes the output in terms of equivalent units: 275 equivalent units of direct materials and 315 equivalent units of conversion costs.
Step 3 computes equivalent unit costs. Direct materials: $ 80; conversion materials: $ 60
Step 4 summarizes total costs to account for and assigns these costs to units completed and to units in ending work in progress.
The costs that get assigned to each of these categories depend, as in all inventory accounting, on the specific assumptions regarding the flow of costs. Next are described to alternative methods, the weighted-average method and the first-in, first-out method.
3. Weighted-average method
The weighted-average process-costing method assigns the average equivalent unit cost of all work done to date (regardless of when it was done) to equivalent units completed and transferred out, and to equivalent units in ending inventory. The weighted-average cost is simply the average of various equivalent unit costs entering the work in process account.
The four -step procedure is used to account for the costs of a subsequent department that has transferred-in costs. Units are fully completed as to transferred-in costs because these costs are just carried forward from the previous process. Direct materials costs have a zero degree of completion in both beginning and ending work-in-process inventories, because in Testing, direct materials are introduced at the end of the process. That completes steps 1 and 2.5.1 Transferred-in Costs and the weigthed-average method
In step 3, the equivalent unit costs are computed. In step 4, the total costs to account for are summarized, that is the total debits to Work in Process under the weighted-average method. After that, these costs are assigned to units completed and to units in ending work-in-process inventory. Beginning work in process and work done in the current period are totaled and merged together for purposes of computing weighted-average costs.
A company may split the Work in Process account into Work in Process - Testing, Transferred-in Costs, Work in Process - Testing, Direct Materials and Work in Process - Testing, Conversion costs. The journal entries would contain this detail, though the underlying reasoning and techniques would be unaffected.
5.2 Transferred-in Costs and the FIFO-Method
The costs transferred-in from the Assembly Department are different when the weighted-average rather than the FIFO method is used in step 3.
In step 4, the total costs to account for are summarized, consisting of the beginning inventory plus costs added during the current period, under the FIFO-method. These costs differ from the total debits to Work on Process under the weighted-average method, because of the different costs of completed units transferred-in from the Assembly Department under the weighted-average and FIFO methods.
When assigning costs, the FIFO method keeps the beginning inventory separate and distinct from the work done during the current period.
Each department in interdepartmental transfers is regarded as being separate and distinct for accounting purposes. All costs transferred in during a given accounting period are carried at one unit cost figure, regardless of whether previous departments used the weighted-average or the FIFO method.
Here are some common pitfalls to avoid when accounting for transferred-in costs:
Cost accounting, chapter 17