When an invoice is issued and you want to change or cancel the invoice with a Credit Note, the system allows you to enter an amount above the invoice amount.

Steps to recreate

1. Open demo company
2. Process an invoice for R500
3. Process a credit note and link it to the above invoice and enter amount of R10000
4. The system allows this.
5. In this case, the company owes the customer R9500
   
   

The issue is known and has been logged as PPAS-461 for investigation.