On the Sales Order (header/lines) it is possible to determine a "Prepayment %". Once the prepayment invoice is posted, there is no information on the posted invoice, about the prepayment %. As there is no field for this. Little enhancement, but could be helpful, if the information would be on the posted invoices (header/lines). Thus, you do not have to calculate prepayment % manually (if it would be needed on the report printout).