Unposting and changing paid invoices

[Geert Janssens]

On 06-06-12 11:19, Axel Essbaum wrote:
> On Jun 5, 2012, at 20:04, Geert Janssens wrote:
>> If the invoice amount stays the same, you can safely do this.
> Excellent, thanks Geert!
>
> Out of curiosity, what breaks if I make a mistake on the invoice amount?
I'm not sure you would really break things, but you could get some 
confusing side effects if you repost an invoice with an amount lower 
than the amount that was paid for the invoice.

Basically, if you unpost the invoice, accidentally lower the amount of 
the invoice and repost it again, GnuCash will note that the payment it 
still has open is more than the invoice and it will create an automatic 
payment forward entry in your A/R account. This automatic payment 
forward will be used to (partly) pay the next invoice that gets posted. 
Since you will be modifying a whole series of invoices, making this 
mistake early on would cause a propagation of automatic payment 
forwards, because the first automatic payment forward created would then 
be used for the next invoice you repost. However, there was already a 
correct payment for this invoice. So now this payment will be split 
again in a part to completely pay the remainder of the invoice (total 
minus payment forward) and the remainder will become another automatic 
payment forward.

In the end if you fix your wrong invoice and apply the last remaining 
automatic payment forward to that invoice, your balance should be 
correct. I'm not too fond of this fix though, because I like to match 
payments with invoices and not with customers. So personally if I ran 
into such a situation, to fix it I would remove all automatic payment 
forwards and probably also all payments linked to the affected invoices 
and then I would re-enter those payments per invoice. But I generally 
try to avoid getting in such a situation in the first place ;)

Geert