1. Compute the total cost to assign to direct labor. 2. Compute the amount of labor-related cost to assign to overhead. 2-3. Cost of Jobs. David Greene's Muffler Shop ("No appointment necessary-we'll hear you coming") uses a normal costing system. Overhead and labor hours were esti- mated at $42,000 and 6,000 hours, respectively, for 2018. During July 2018, only 40 jobs were finished. Materials used on these jobs totaled $3,700 and labor costs were $2,700 (at $20 per hour). During 2018,5,000 labor hours were worked and $38,000 in overhead costs were incurred