Discount Field and Credit Notes

The discount field on invoices is useful to us, as a retail/wholesale operation we charge our wholesale customers the prices we charge in our retail outlet and give them a discount on it.

• It would be good to have the discount attached to the customer record, so it is automatic and we can allocate an appropriate discount for each customer, according to the level of trade with us, rather than doing it manually with each invoice.
  We raise a credit note when a customer returns unsold goods supplied on sale-or-return.
• it would be good to be able to apply and calculate discounts automatically on credit notes as well as invoices, the discount box isn't there on credit notes, so we have to calculate the discount by hand and put in a negative line.
  The treatment of credit notes in statements is confusing. Because you use a strict allocation model, allocating payments to specific invoices rather than just to accounts, credit notes don't appear on statements as such, but only as part-paid invoices, and then only if we have allocated them to an invoice. This is potentially confusing to the customer who gets such a statement but knows full well he or she hasn't paid any part of any invoices. It would, I think, be preferable just to post the credit note (and, for that matter, any payments) to the customer account, so balances are always kept and shown at account level rather than invoice level, regardless of allocation.