Keel Company’s fixed overhead costs for the year are expected to be as follows: depreciation, $72,000; supervisory salaries, $92,000; property taxes and insurance, $26,000; and other fixed overhead, $14,500. Total fixed overhead is thus expected to be $204,500. Variable costs per unit are expected to be as follows: direct materials, $16.50; direct labor, $8.50; operating supplies, $2.60; indirect labor, $4.10; and other variable overhead costs, $3.20. Prepare a flexible budget for the following levels of production: 18,000 units, 20,000 units, and 22,000 units. What is the flexible budget formula for the year ended December 31?