Exercise 18-6 PCB Corporation manufactures a single product. Monthly production costs incurred in the manufacturing process are shown below for the production of 3,294 units. The utilities and maintenance costs are mixed costs. The fixed portions of these costs are $329 and $220, respectively ni 3,294 Direct materials Direct labor Utilities Property taxes Indirect labor Supervisory salaries Maintenance Depreciation $8,235 19,764 2,306 1,098 4,941 2,086 1,208 2,635