[GNC] Forcing a single payment to split across invoices with the older one not being paid in full

[Geert Janssens]

Op maandag 6 augustus 2018 22:05:06 CEST schreef Adrien Monteleone:
> I have a customer that has several invoices open. The oldest one is rather
> large so they are paying in installments. But when they pay these
> installments they are also paying newer smaller invoices.
> 
> But when I enter a payment GnuCash won’t let me split the payment between
> the two. It forces the entire payment to the older invoice. (yes, I
> selected both in the Process Payment window) This leaves the newer smaller
> invoice as ‘unpaid’ and the older invoice as having more payment applied to
> it than should be.
> 
> I can’t fix this in lots (as far as I can tell) since there is only the one
> split.
> 
> If I try to adjust the payment transaction (from my cash account - not A/R),
> that is, I’ve tried changing the amount posted to A/R to reflect the larger
> payment on the older invoice, and then manually add a split to cover the
> new invoice, and then ‘Edit Payment’ but GnuCash complains that one of the
> splits is in a business account that isn’t a business transaction and tells
> me it’s going to be ignored.
> 
> So what I have is something like this:
> 
> Dr. Cash	$500
> Cr. A/R			$500
> 
> But what I need is this:
> 
> Dr. Cash	$500
> Cr. A/R			$450
> Cr. A/R			$ 50
> 
> If the older invoice was being paid in full, this would work just fine, but
> there is still a balance. GnuCash won’t let me split this payment and
> retain everything in a single transaction. I suppose I could create two
> separate payment transactions, but then this breaks up the actual customer
> payment amount and makes it look like two payments instead of one.
> 
> Any ideas?

A use case that wasn't fully taken into account when redesigning the payment 
window (although it did cross my mind at later times).

What you can try is
- create a payment (via Process Payment)
- select only the smaller, more recent invoice
- adjust the payment amount to the full amount you received from your customer
- click ok

Assuming you don't have automatic payment forwarding enabled (see my reply on 
credit notes), this will create a prepayment for the difference between the 
client's payment and the invoice you assigned.

- Now reopen process payment and select the older, large invoice and the 
prepayment.
- Set the remaining amount to pay to 0
- click ok

I *think* that should give you the assignments as you want.

Regards,

Geert