Vendor invoice Discount & Extra charge

To enter a discount and/or an extra charge for the invoice, press "Actions" and then "Discount & Extra charge":

You may add them whether as a percentage or flat amount.

To do that, select the corresponding extra charge and discount type (Percentage or Absolute) and enter the requred value:

Press "Save" after entering, and you'll go back to the Vendor invoice page.

Note: Invoices with zero or negative amounts cannot be linked to payments.