I was setting up discounts for Sap Customer Checkout, and it says in the Integration Guide that Discounts of discount groups, are applied as discount to the sales item in SAP Customer Checkout.
But when it comes to Special Prices for Business Partners and Period and Volume Discounts, the system applies the discounts to Price list and takes the price with an applied amount as a new price to Customer Checkout without showing how much discount was applied in the Discount Cell.
So During Period and Volume Discounts, the Discounts are applied as a new price to sales items in Sap Customer Checkout and not as a discount. (The discount Cell is blank or shows 0 instead of showing for e.g 20%)
Now I think that the reason behind this is to make it easier to add additional discounts when selling an item using Periods and Volume discount. But i think there should exist a cell that shows information about the discount, So the users could track how much discount is being applied to an item.