koebel corp. uses a job order costing system with manufacturing overhead applied to products on the basis of direct labor hours. for the upcoming year, koebel corp estimated total manufacturing overhead cost at $564,300 and total direct labor hours of 51,300. koebel corp. started the year with no beginning balances in either work in process inventory or finished goods inventory. during the year actual manufacturing overhead incurred was $549,200 and 47,700 direct labor hours were used.