Amount
To activate this field, select Amount in the Discount Type field. The Amount field allows you to enter a numeric discount value. The value entered here is converted to a ratio of the amounts on the Amounts tab using the following formula:
Order Discount = Amt * 100/Total Price - Freight - Misc Chgs - (Sales Tax) - (Sales Tax 2) - Accum Freight - Accum Misc Chgs - [Accum] (Sales Tax) - [Accum] (Sales Tax 2)
This ratio is the new Order Discount. The data in the Amount field is not stored in the database. It is used only to calculate the Order Discount (which is stored).
When calculating discounts for an order, the system will apply any line item level discounts that exist to each line. Then it applies the order level discount to the sum of the lines.