Problem 24-07A Sheffield Corporation manufactures a single product. The standard cost per unit of product is shown below. Direct materials-3 pound plastic at $6.00 per pound Direct labor-1.5 hours at $11.00 per hour Variable manufacturing overhead Fixed manufacturing overhead Total standard cost per unit $ 18.00 16.50 10.50 7.50 $52.50 The predetermined manufacturing overhead rate is $12 per direct labor hour ($18.00 = 1.5). It was computed from a master manufacturing overhead budget based on normal production of 7,800 direct labor hours (5,200 units) for the month. The master budget showed total variable costs of $54,600 ($7.00 per hour) and total fixed overhead costs of $39,000 ($5.00 per hour). Actual costs for October in producing 4,500 units were as follows. Direct materials (13,690 pounds) Direct labor (6,590 hours) Variable overhead Fixed overhead $ 84,878 75,126 61,560 21,540 $243,104 Total manufacturing costs The purchasing department buys the quantities of raw materials that are expected to be used production each month. Raw materials inventories, therefore, can be ignored. Compute the overhead controllable variance and the overhead volume variance Overhead controllable variance Overhead volume variance S