(b) absorptiontu 4. Which costing method, variabl Ur u Explain. ses Support department cost allocation; plantwide versus departmental overhead rates; product costing cost drivers: manufacturer Rising Fast Pty Ltd manufactures a complete line of fibreglass attach cases and suitcases. The firm has three manufacturing departments: moulding, component and assembly. There are also two support departments: power and maintenance. The sides of the cases are manufactured in the moulding department. The frames, hinges and locks are manufactured in the component department. The cases are pleted in the assembly department. Varying amounts of materials and time are required to manufacture each type of case. Rising Fast has always used a plantwide overhead rate. Direct labour hours are used to assign overhead to products. The predetermined overhead rate is calculated by dividing the company's total estimated overhe by the total estimated direct labour hours to be worked in the three manufacturing departments. ad Liam Bolt, manager of cost accounting, has recommended that Rising Fas rates. Th t use departmental overhead e planned operating costs and expected levels of activity for the coming year have been developed oit and are presented by department in the following schedules. (All numbers are in thousands.)