NSF Lube is a fast-growing chain of oil-change stores. The following data are available for last year's services. NSF Lube performed 468,700 oil changes last year. It had budgeted 434,600 oil changes, averaging 10 minutes each. Standard variable labor and support costs per oil change were as follows. Direct oil specialist services: 10 minutes at $27 per hour Variable support staff and overhead: 9.0 minutes at $22 per hour Fixed overhead costs: Annual budget $1,038,600 Fixed overhead is applied at the rate of $2.40 per oil change. Actual oil change costs: $4.50 3.30 Direct oil specialist services: 468,700 changes averaging 20 minutes at $30 per hour $4,687,000 Variable support staff and overhead: 0.18 labor-hours at $15 per hour 468,700 changes Fixed overhead 1,265,490 1,395,000 Required: a. Prepare a cost variance analysis for each variable cost for last year. b. Prepare a fixed overhead cost variance analysis.