Andrews Construction assembles residential houses. It uses a job-costing system with two direct-cost categories (direct materials and direct labor) and one indirect-cost pool (assembly support). Direct labor-hours is the allocation base for assembly support costs. In December 2016, Andrews budgets 2017 assembly-support costs to be $8,100,000 and 2017 direct labor-hours to be 135,000. At the end of 2017, Andrews is comparing the costs of several jobs that were started and completed in 2017. Compute the (a) budgeted indirect-cost rate and (b)actual indirect-cost rate. Why do they differ?