Exercise 4-3 Supertronic Plastics produces parts for a variety of small machine manufacturers. Most products go through two operations, molding and trimming, before they are ready for packaging. Expected costs and activities for the molding department and for the trimming department for 2009 follow. Data for two special order parts to be manufactured by the company in 2009 follow: Required 1. Compute the plantwide overhead rate using direct labor hours as the base. 2. Determine the overhead cost assigned to each product line using the plantwide rate computed in requirement 1 . 3. Compute a departmental overhead rate for the molding department based on machine hours and a department overhead rate for the trimming department based on direct labor hours. 4. Determine the total overhead cost assigned to each product line using the departmental overhead rates from requirement 3 . 5. Determine the overhead cost per unit for each product line using the plantwide rate. Compare these costs to the cost per unit if departmental rates were used