Calculating Plantwide Predetermined Overhead Rate. Manufacturing overhead costs totaling $5,000,000 are expected for this coming year. The company also expects to use 100,000 direct labor hours and 40,000 machine hours. Calculate the plantwide predetermined overhead rate using direct labor hours as the base. Provide a one-sentence description of how the rate will be used to allocate overhead costs to products. Calculate the plantwide predetermined overhead rate using machine hours as the base. Provide a one-sentence description of how the rate will be used to allocate overhead costs to products