Hi, we are trying to use the Customer Payment Journal's Deduction feature for customer payments taking an arbitrary deduction not tied to a specific invoice. It works fine when there are no shortpayments - the invoices are settled in full, and a Deduction voucher is created for the deduction.
The issue we are having is when one of multiple invoices is being shortpaid in addition to the arbitrary deduction - we cannot find a way to control which invoice doesn't get settled in full - D365 keeps shorting the settlement of the last / newest invoice.
Here is an example where we tried to settle a payment of two invoices with a $10 arbitrary deduction AND a $10 shortpayment on the oldest invoice.
Normally we use the Enter Customer Payments form, and specify the shortpaid invoice in the Amount To Pay field:

We have also tried using the Customer Payments form > Settle Transactions link, and specifying the shortpaid invoice in the Amount To Settle field:
After using the Customer Payments form > Deductions link and creating a $10.00 deduction, the Deduction voucher line is shown below the invoice(s) payment voucher line.
However after we Post, we see that D365 settled the older invoice in full and shorted the settlement of the newer invoice instead:
Does anyone have any experience with this or suggestions to try? Thanks.