Working with a prospect.

Order Entry - we would like to enter a % Discount per line item.
I am looking at the Invoice that they currently print from BV, and the detail lines include that following columns:
- Qty Ordered
- Qty Shipped
- Unit Price
- % Discount
- Extended Amount

Is there any way in OE that we could enter a line discount? (This would have to be at the Detail level, as their Invoice shows different discounts for different SKUs.)