Notice that in Exhibit 10-9 foremen salaries are a fixed expense, indirect labor is a variable expense and miscellaneous expenses are a step expense. When the table format is used, a problem often arises when budget amounts are needed for some activity level between activity levels for which budget amounts are provided. Two approaches to this problem are used :
1. Use the budget amount nearest to the needed activity level. For example, if the budget for 460,000 direct machine hours were needed, the expense at 450,000 direct machine hours would be used.
2. Determine the needed budget amount by straightline interpolation. The budget amount for 460,000 direct machine hours would be computed as follows: