Under the perpetual inventory system, what is the difference between a sales return and a sales allowance? Yantnz: A sales return reduces the amount receivable from the customer, but a sales allowance does not. A sales return involves an adjustment to Merchandise Inventory, but a sales allowance does not. 0 A sales return requires a debit to Sales Returns and Allowances, but a sales allowance does not. A sales return is not deducted from sales revenue to calculate net sales, but a sales allowance is deducted from sales revenue. O