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 Direct-Labor Manufacturing Month January February March April May June Hours 18,000 20,000 29,000 21,000 25,000 23,000 Overhead $682,000 721,000 880,000 749,500 777,000 774,000 March's costs consisted of machine supplies ($110,200), depreciation ($23,000), and plant maintenance ($746,800). 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 $68,000. The cost is $136,000 from 15,000-29,999 hours and $204,000 when activity reaches 30,000 hours or more