Apply discount lines (-ve amt) on AP Invoice lines and process payment

Summary:

The business have received AP invoice with 2 discount amounts (negative amount). PO line is GST applicable and matched to Invoice. The discount lines are GST Free

Line 1 = $3,846.11 GST_PURCHASE

Line 2 = -$310.50 GST_PURCHASE_FREE

Line 3 = -$109.17 GST_PURCHASE_FREE

Applying the credits to line 1 would create a variance in the GST amount so inappropriate. How do we complete AP invoice and payment process for above scenario? given we cannot Edit PO to add negative PO lines.

Content (required):

Version (include the version you are using, if applicable):

Oracle Cloud Payables and Payments (21D)

Code Snippet (add any code snippets that support your topic, if applicable):