What are the three key advantages of the plant wide and departmental overhead rate overhead allocation methods?

The departmental overhead rate is an expense rate calculated for each department in a factory production process. The departmental overhead rate is different at every stage of the production process when various departments perform selected steps to complete the final process.

By breaking up overhead costs for individual business sections rather than having a company-wide rate, management can assess corporate inefficiencies more accurately and take more specific action.

An overhead rate, in managerial accounting, is an additional cost added on to the direct costs of production in order to more accurately assess the profitability of each product. To allocate these costs, an overhead rate is applied that spreads the overhead costs around depending on how much resources a product or activity used.

For example, overhead costs may be applied at a set rate based on the number of machine hours required for the product. In more complicated cases, a combination of several cost drivers may be used to approximate overhead costs.

The departmental overhead rate is specific to every segregated step in the entire process. For example, if a company makes bread, different departmental rates could be used for the actual production/manufacturing line and the bagging process.

Cost-cutting, efficiency and productivity are standard elements of a strong corporate performance methodology. Analysis and benchmarking of departmental overhead rates is an effective way to measure success. Comparisons between competitors, as well as among various internal departments help isolate efforts that are adding value, and those that are destroying enterprise value.

No two cost-cutting approaches are the same. Like all things in business, there are pros and cons to the myriad of strategies businesses can utilize. However, by following trends in departmental rates, patterns do emerge highlighting the delicate balance of short-term goals with long-term business requirements.

Determining appropriate departmental rates is an area addressed by managerial accounting methods. Managerial accounting is the process of identifying, measuring, analyzing, interpreting and communicating information for the pursuit of an organization's goals.

This branch of accounting is also known as cost accounting. The key difference between managerial and financial accounting is managerial accounting information is aimed at helping managers within the organization make decisions, while financial accounting is aimed at providing information to parties outside the organization.

In managerial accounting, rather than using one overhead rate to allocate all of the overhead costs, overhead costs can be broken down by departments. Departmental overhead rates offer the flexibility to use a different activity or cost driver for each department. Often, some departments will rely heavily on manual labor while others require more machinery. Direct labor hours can be important to certain departments but machine hours might work better for others.

Using the appropriate overhead rates for a business helps managers with budgeting, job costing and product pricing. Different types of allocation methods result in varying figures for the same enterprises. Some businesses use the simple method of a single overhead rate. Others break the cost down by department. Therefore, choosing the method that provides the most accurate results for a particular business can help the owners and managers remain competitive within a given industry.

Single Overhead Rates

  1. Single overhead rates apply cost allocations for expenses incurred across the entire plant. Common overhead rates include cost allocations for such expenses as indirect materials, indirect labor, utilities expenses, insurance and property taxes, as well as depreciation of buildings, furnishings and equipment. Single overhead rates are figured by dividing the total cost of overhead by cost drivers common throughout each department or section of the business. Cost drivers can be defined as the primary reasons for indirect costs.

Separating Rates

  1. Departmental and manufacturing overhead rates are those calculated for each separate department. This rate is figured by dividing the total department overhead budgeted by the budgeted amount of the common cost drivers within the department. For example, in a manufacturing business, the machining department may use machine-hours to figure overhead rates when calculating job costs. Contrastingly, the shipping department may use labor hours to figure overhead rates. Other areas of a plant that produces multiple products may allocate overhead rates of either machine-hours or labor to the budgeted job costs depending on the main activity of each department.

Using the Calculations

  1. In using departmental and manufacturing overhead rates to determine product costs, indirect costs necessary for normal business operation should be added in to budget allocations. For example, rent, insurance and utilities, which are overhead costs plant-wide, each play a necessity to varying extents from department to department. Within a large manufacturing business with departments ranging from sales to assembly to administration, separating overhead rates gives management a clearer picture of the price of production.

Benefits

  1. Using a plant-wide or single overhead rate when a business manufactures or produces a single product or provides a single service is feasible and generally accurate. However, in a business with multiple departments and manufacturing sections, a much more accurate overhead rate can be calculated through cost allocation per department. For example, in a business that produces dozens of products, it is essential to know the cost of producing each product. Knowing what overhead costs are incurred in what departments within the business gives management a clearer understanding of how to price individual products and service competitively.

Question: Managers at companies such as Hewlett-Packard often look for better ways to figure out the cost of their products. When Hewlett-Packard produces printers, the company has three possible methods that can be used to allocate overhead costs to products—plantwide allocation, department allocation, and activity-based allocation (called activity-based costing). How do managers decide which allocation method to use?

Answer: The choice of an allocation method depends on how managers decide to group overhead costs and the desired accuracy of product cost information. Groups of overhead costs are called cost poolsA collection of overhead costs, typically organized by department or activity.. For example, Hewlett Packard’s printer production division may choose to collect all factory overhead costs in one cost pool and allocate those costs from the cost pool to each product using one predetermined overhead rate. Or Hewlett Packard may choose to have several cost pools (perhaps for each department, such as assembly, packaging, and quality control) and allocate overhead costs from each department cost pool to products using a separate predetermined overhead rate for each department. In general, the more cost pools used, the more accurate the allocation process.

Question: Let’s look at SailRite Company, which was presented at the beginning of the chapter. The managers at SailRite like the idea of using the plantwide allocation method to allocate overhead to the two sailboat models produced by the company. How would SailRite implement the plantwide allocation method?

Answer: The plantwide allocationA method of allocating costs that uses one cost pool, and therefore one predetermined overhead rate, to allocate overhead costs. method uses one predetermined overhead rate to allocate overhead costs. One cost pool accounts for all overhead costs, and therefore one predetermined overhead rate is used to apply overhead costs to products. You learned about this approach in Chapter 2 "How Is Job Costing Used to Track Production Costs?" where one predetermined rate—typically based on direct labor hours, direct labor costs, or machine hours—was used to allocate overhead costs. (Remember, the focus here is on the allocation of overhead costs. Direct materials and direct labor are easily traced to the product and therefore are not a part of the overhead allocation process.)

Using SailRite Company as an example, assume annual overhead costs are estimated to be $8,000,000 and direct labor hours are used for the plantwide allocation base. Management estimates that a total of 250,000 direct labor hours are worked annually. These estimates are based on the previous year’s overhead costs and direct labor hours and are adjusted for expected increases in demand the coming year. The predetermined overhead rate is $32 per direct labor hour (= $8,000,000 ÷ 250,000 direct labor hours). Thus, as shown in Figure 3.1 "Using One Plantwide Rate to Allocate SailRite Company’s Overhead", products are charged $32 in overhead costs for each direct labor hour worked.

Figure 3.1 Using One Plantwide Rate to Allocate SailRite Company’s Overhead

What are the three key advantages of the plant wide and departmental overhead rate overhead allocation methods?

Question: Assume SailRite uses one plantwide rate to allocate overhead based on direct labor hours. What is SailRite’s product cost per unit and resulting profit using the plantwide approach to allocate overhead?

Answer: The calculation of a product’s cost involves three components—direct materials, direct labor, and manufacturing overhead. Assume direct materials cost $1,000 for one unit of the Basic sailboat and $1,300 for the Deluxe. Direct labor costs are $600 for one unit of the Basic sailboat and $750 for the Deluxe. This information, combined with the overhead cost per unit, gives us what we need to determine the product cost per unit for each model.

Given the predetermined overhead rate of $32 per direct labor hour calculated in the previous section, and assuming it takes 40 hours of direct labor to build one Basic sailboat and 50 hours to build one Deluxe sailboat, we can calculate the manufacturing overhead cost per unit. Manufacturing overhead cost per unit is $1,280 (= $32 × 40 direct labor hours) for the Basic boat and $1,600 (= $32 × 50 direct labor hours) for the Deluxe boat. Combine the manufacturing overhead with direct materials and direct labor, as shown in Figure 3.2 "SailRite Company Product Costs Using One Plantwide Rate Based on Direct Labor Hours", and we are able to calculate the product cost per unit.

Figure 3.2 SailRite Company Product Costs Using One Plantwide Rate Based on Direct Labor Hours

What are the three key advantages of the plant wide and departmental overhead rate overhead allocation methods?

*$1,280 = 40 direct labor hours per unit × $32 rate.

**$1,600 = 50 direct labor hours per unit × $32 rate.

The average sales price is $3,200 for the Basic model and $4,500 for the Deluxe. Using the product cost information in Figure 3.2 "SailRite Company Product Costs Using One Plantwide Rate Based on Direct Labor Hours", the profit per unit is $320 (= $3,200 price – $2,880 cost) for the Basic model and $850 (= $4,500 price – $3,650 cost) for the Deluxe. Recall from the opening dialogue that SailRite’s overall profit has declined ever since it introduced the Deluxe model even though the data shows both products are profitable.

Question: The managers at SailRite like the idea of using the plantwide allocation approach, but they are concerned that this approach will not provide accurate product cost information. Although the plantwide allocation method is the simplest and least expensive approach, it also tends to be the least accurate. In spite of this weakness, why do some organizations prefer to use one plantwide overhead rate to allocate overhead to products?

Answer: Organizations that use a plantwide allocation approach typically have simple operations with a few similar products. Management may not want more accurate product cost information or may not have the resources to implement a more complex accounting system. As we move on to more complex costing systems, remember that these systems are more expensive to implement. Thus the benefits of having improved cost information must outweigh the costs of obtaining the information.

Question: Assume the managers at SailRite Company prefer a more accurate approach to allocating overhead costs to its two products. As a result, they are considering using the department allocation approach. How would SailRite form cost pools for the department allocation approach?

Answer: The department allocationA method of allocating costs that uses a separate cost pool, and therefore a separate predetermined overhead rate, for each department. approach is similar to the plantwide approach except that cost pools are formed for each department rather than for the entire plant, and a separate predetermined overhead rate is established for each department. Remember, total estimated overhead costs will not change. Instead, they will be broken out into various department cost pools. This approach allows for the use of different allocation bases for different departments depending on what drives overhead costs for each department. For example, the Hull Fabrication department at SailRite Company may find that overhead costs are driven more by the use of machinery than by labor, and therefore decides to use machine hours as the allocation base. The Assembly department may find that overhead costs are driven more by labor activity than by machine use and therefore decides to use labor hours or labor costs as the allocation base.

Assume that SailRite is considering using the department approach rather than the plantwide approach for allocating overhead. The cost pool in the Hull Fabrication department is estimated to be $3,000,000 for the year, and the cost pool in the Assembly department is estimated at $5,000,000. Note that total estimated overhead cost is still $8,000,000 (= $3,000,000 + $5,000,000). Machine hours (estimated at 60,000 hours) will be used as the allocation base for Hull Fabrication, and direct labor hours (estimated at 217,000 hours) will be used as the allocation base for Assembly. Thus two rates are used to allocate overhead (rounded to the nearest dollar) as follows:

  1. Hull Fabrication department rate: $50 per machine hour (= $3,000,000 ÷ 60,000 hours)
  2. Assembly department rate: $23 per direct labor hour (= $5,000,000 ÷ 217,000 hours)

As shown in Figure 3.3 "Using Department Rates to Allocate SailRite Company’s Overhead", products going through the Hull Fabrication department are charged $50 in overhead costs for each machine hour used. Products going through the Assembly department are charged $23 in overhead costs for each direct labor hour used.

Figure 3.3 Using Department Rates to Allocate SailRite Company’s Overhead

What are the three key advantages of the plant wide and departmental overhead rate overhead allocation methods?

The department allocation approach allows cost pools to be formed for each department and provides for flexibility in the selection of an allocation base. Although Figure 3.3 "Using Department Rates to Allocate SailRite Company’s Overhead" shows just two rates, many companies have more than two departments and therefore more than two rates. Organizations that use this approach tend to have simple operations within each department but different activities across departments. One department may use machinery, while another department may use labor, as is the case with SailRite’s two departments. This approach typically provides more accurate cost information than simply using one plantwide rate but still relies on the assumption that overhead costs are driven by direct labor hours, direct labor costs, or machine hours. This assumption of a causal relationship is increasingly less realistic as production processes become more complex.

The plantwide and department allocation methods are “traditional” approaches because both typically use direct labor hours, direct labor costs, or machine hours as the allocation base, and both were used prior to the creation of activity-based costing in the 1980s.

Key Takeaway

  • Regardless of the approach used to allocate overhead, a predetermined overhead rate is established for each cost pool. The plantwide allocation approach uses one cost pool to collect and apply overhead costs and therefore uses one predetermined overhead rate for the entire company. The department allocation approach uses several cost pools (one for each department) and therefore uses several predetermined overhead rates.

Kline Company expects to incur $800,000 in overhead costs this coming year—$200,000 in the Cut and Polish department and $600,000 in the Quality Control department. Total annual direct labor costs are expected to be $160,000. The Cut and Polish department expects to use 25,000 machine hours, and the Quality Control department plans to utilize 50,000 hours of direct labor time for the year.

Required:

  1. Assume Kline Company allocates overhead costs with the plantwide approach, and direct labor cost is the allocation base. Calculate the rate used by the company to allocate overhead costs.
  2. Assume Kline Company allocates overhead costs with the department approach. Calculate the rate used by each department to allocate overhead costs.

Solutions to Review Problem 3.2

  1. The plantwide rate is calculated as follows:

    Predetermined overhead rate=Estimated overhead costsEstimated activity in allocation base=$800,000$160,000=$5 per $1 in direct labor cost=500% of direct labor cost
  2. The department rates are calculated using the same formula as the plantwide rate. However, overhead costs and activity levels are estimated for each department rather than for the entire company, and two separate rates are calculated:

    Cut and Polish department=$200,00025,000 machine hours=$8 per machine hour Quality Control  department=$600,00050,000 direct labor hours=$12 per direct labor hour