Resolution: 

To issue a discount to show on the Invoice an  Add-on in the Billing Terms is needed.

1. Go to Billing > Billing terms.
2. Select the project want to offer a discount on.
3. Select the Add-on tab.
4. Click the box to Add-on Fee.
5. Click Insert to add a line.
6. Enter a Sequence Number 1 if no other add-ons are listed.
7. Enter a Description, example: Discount.
8. Click either User Amt to deduct a specific amount or enter a Percent to apply.
9. If using an Amount, enter a negative amount to decrease the invoice by the specific amount.
10. If using Percent, enter a negative percent to decrease the invoice by the percent specified.
11. If using Percent, check the box on which section of the invoice to apply this discount to: Labor, Expense, Consultant, fee, and/or Units.
12. Save.