Error: "Credit note amount cannot exceed the total paid amount of the selected invoices"

Issue Description:

When attempting to issue a Credit Note against an invoice, the system blocks saving and returns the error:

‘Credit note amount cannot exceed the total paid amount of the selected invoices.’

Root Cause & Validation Rules:

• Refund Credit Notes: Designed strictly to process cash/bank refunds. Requires an existing payment transaction record (Amount less than equal Paid Amount). You cannot issue a refund for money that was never collected.

• Adjustment Credit Notes: Designed to write off or reduce open invoice balances (Amount less than equal Outstanding Amount).
  
  

Resolution Steps:

1. For Fully Unpaid Invoices (Issue Adjustment CN from Invoice View Page):

   • Go into the Unpaid Invoice you want to issue.

   • Click 3 dots at the top-right menu and select Create Credit Note.

   • Select the items you want to knock-off with Credit Note (or set the reason/type to Discount / Goods Return).

   • Ensure the CN total matches the unpaid balance, then save to knock off the invoice balance.

2. For Partially Paid Invoices:

   • To Refund Collected Cash: Process a Refund CN up to the exact amount received (Paid Amount).

   • To Offset Unpaid Balance: Process an Adjustment CN from the invoice More menu for the remaining balance (Outstanding Amount).