1. Amount Received & Change to Return When a customer paid more than the invoice amount, I could simply enter the amount received, and the system automatically calculated the balance amount to be returned. This is extremely useful during rush hours, as it reduces calculation errors and makes billing faster. 2. Total Quantity / Total Items The previous system also displayed the total quantity of products in the invoice. For example, if I punched 10 different products with different quantities, I could immediately see the total number of pieces sold without manually counting them.