At the bottom of the Invoicing plan tab you will find extra information for each partial invoice row.
VAT Code
The VAT code selected in the quote header will be shown here, but this can be changed. You can have different VAT codes on the partial invoice rows. The VAT codes must be registered in the Update VAT Rates procedure in Global Settings. For invoices that concern deliveries you cannot change VAT code.
Payment Terms
This field shows the payment term entered on the partial invoice row in the invoicing plan selected in the quote header, but it can be changed here. You can therefore have different terms of payment on the partial invoice rows. For delivery invoices, the payment term entered in the quote header will be used. This payment term cannot be changed.