Required information The following selected data were taken from the accounting records of Metcalf Manufacturing. The company uses direct-labor hours as its cost driver for overhead costs. March's costs consisted of machine supplies ($248,400), depreciation ($31,000), and plant maintenance ($616,600). These costs exhibit the following respective behavior: variable, fixed, and semivariable. The manufacturing overhead figures presented in the preceding table do not include Metcalf's supervisory labor cost, which is step-fixed in nature. For volume levels of less than 15,000 hours, supervisory labor amounts to $76,000. The cost is $152,000 from 15,000 to 29,999 hours and $228,000 when activity reaches 30,000 hours or more. 5. Assume that a company has a step-fixed cost. Generally speaking, where on a step should the firm attempt to operate if it desires to chieve a maximum return on its investment