Lapp Manufacturing uses flexible budgets to control its selling expenses. Monthly sales are expected to be from $400,000 to $480,000. Variable costs and their percentage relationships to sales are: Sales commissions Advertising Traveling Delivery 6% 4% 5% 1% Fixed selling expenses consist of sales salaries $80,000 and depreciation on delivery equipment $20,000. Prepare a flexible budget for increments of $40,000 of sales within the relevant range. Monthly Flexible Selling Expense Budget $