E-M:8-15 Preparing a flexible budget Office Plus sells its main product, ergonomic mouse pads, for $13 each. Its variable cost is $5.10 per pad. Fixed costs are $205,000 per month for volumes up to 65,000 pads. Above 65,000 pads, monthly fixed costs are $250,000. Prepare a monthly flexible budget for the product, showing sales revenue, variable costs, fixed costs, and operating income for volume levels of 45,000, 55,000, and 75,000 pads