Code review comment for lp:~camptocamp/account-invoicing/7.0-account_invoice_zero

Hi, Guewen, the case you told it's also forbidden. Let me explain: the only official mechanism for compensating invoices is via refunds. You don't need to make cash flows, but you need to have both documents. That is theoretically. In practice, if you have an amount to compensate (a potential refund) that is lower than the amount of the invoice, it's a common and tolerated practise to discount it from the invoice, but never if the amount is equal.

I hope I explain it well.

Regards.