Sometimes a customer only has $6 cash or 6.00 remaining on their debit card on an order that costs $6.44. With tax included, a cashier can't just apply a $.44 discount to clear the order, because as the discount is added, the amount of tax decreases and a $.44 item discount would decrease the tax amount too, resulting in an overpayment. So the cashier might try $.43 or $.42. Not fun.
"Discount Balance" is a new button that figures out the right discount to apply get to a zero balance with just one tap. Easy.
Discount appears as "Remaining Balance" Discount for tracking purposes.