Predetermined Factory Overhead Rate Road Runner Engine Shop uses a job order cost system to determine the cost of performing engine repair work. Estimated costs and expenses for the coming period are as follows: Engine parts $$1,102,900$ Shop direct labor $805,000$ Shop and repair equipment depreciation $31,500$ Shop supervisor salaries $87,500$ Shop property taxes $15,900$ Shop supplies $12,100$ Advertising expense $22,100$ Administrative office salaries $94,800$ Administrative office depreciation expense $12,100$ Total costs and expenses $$2,183,900$ The average shop direct labor rate is $$23$ per hour.