Process vendor payments and negative values

[Graham Leggett]

Derek Atkins wrote:

> I dont understand what you mean here.  Just because you process payments
> in reverse order shouldn't mean anything.  So long as you don't change
> the posted invoices then the payments will eventually add up.  For example:
> 
> Jan 1 invoice $100
> Feb 1 invoice $150
> Feb 15 payment -$150
> Feb 20 payment -$100
> 
> This should all add up just fine.  The $150 will apply $100 to the
> Jan 1 invoice and $50 to the Feb 1 invoice.  Then the Feb 20 payment
> will apply the remaining $100 to the Feb 1 invoice.
> 
> So, unless you changed any values after-the-fact, it should be just
> fine.
> 
> Hmm, now that I think about it...  It _might_ cause a problem if you:
> post invoice, apply payment (such that invoice is paid), then unpost
> the invoice, reduce its amount, and then repost it.  I _think_ this is
> handled correctly, but it might not be.

I think this is possibly what happened - I remember a few months back 
that bills had been posted with the wrong dates (affecting the VAT 
calculations), and were corrected.

I did a further test by applying an extra arbitrary payment of R1000 to 
the account to see where it came off. It resulted in a payable aging 
that looked like this:

30 days: R0.00
60 days: R0.00
90 days: R0.00
120 days: R-1000.00

Should the amount not have been listed under 30 days instead?

> Sure there is!  Check your A/R account.  There is 80.30 from 30 days
> ago and 80.30 from 120+ days ago.

There isn't - all the bill amounts are in the region of around R1200 
each, the stray amount represents the difference between a bill and a 
debit order payment that was incorrectly made, then corrected.

> What is a "negative amount"?  There are "invoices" and there are
> "payments".  You cannot have a "negative invoice" nor can you have a
> "negative payment".  Also, you can only have one "invoice" per lot.
> So, if you somehow got an invoice+payment lot out of balance by, say,
> hand-modifying a payment transaction, that could easily have caused
> this problem.  But I don't know what you mean by the above.

None of the payments have been hand modified that I can remember.

Can I send you a copy of the file privately so you can see what is 
happening? It's a bit difficult to explain.

Regards,
Graham
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