Module 4 Discussion - Mark Wallace Refer to the chapter opener regarding Mark Wallace and his company, Wallace Detroit Guitars. All successful businesses track their costs, and it is especially important for start-up businesses to monitor and control costs. Required 1. Assume that Mark uses a job order costing system. For the basic cost category of direct materials, explain how Mark's job cost sheet would differ from a job cost sheet for a service company. 2. For the basic cost categories of direct materials, direct labor, and overhead, provide examples of the types of costs that would fall into each category for Wallace Detroit Guitars