Over payments not being brought forward

Could someone give me some advice please? A customer has made an overpayment in lieu of work to be done. This work has now been done and have created an invoice for the customer. For some reason, the overpayment is not being brought forward and being deducted from the new invoice.
In the customer listing, it shows a credit amount. Just can’t get my head around how to resolve it.
Thank you in advance

Once a receipt is posted to a specific invoice, it remains associated with that invoice. Read this Guide to see how to handle such a situation: Resolve overpaid status on sales invoices | Manager.

Yes, this is a “feature” of manager, if you receive (or make) an over-payment for an invoice, manager does not automatically only pay just that amount and place the remainder in credit for that client, you need to either:

a) break the payment up yourself into two components:

  1. only allocate the exact due payment to the invoice in question, and
  2. create a second line item in the receipt payment with no invoice allocated to that remainder. This will leave the remainder floating as a credit for them, or

b) never allocate payments to invoices and let manager allocate accordingly. This may or may not suit your needs. It often works ok for me, but it can be cumbersome in my use-case, since for various reasons I pay some invoices before others (deliberately). But it is more cumbersome managing a single payment over multiple invoices individually, so it’s best to let manager do it for you. YMMV

Thank you both for your quick responses.
It makes so much sense now someone has explained it to me.
Life is a learning curve

Manager previously followed two different approaches for overpayments. In the first, they were posted to an automatic control account named Customer credits. Then, the approach was simplified and Customer credits was rolled under Accounts receivable with overpayments automatically allocated to unpaid invoices. This caused problems for many users as they chased rolling allocations. So the current implementation was adopted. Now, receipts remain fixed to a sales invoice when so designated.

Accountants (and Manager users) are divided on whether the Customer credits approach was better. It was certainly more complex and harder for inexperienced users to understand. Both approaches are fundamentally correct accounting.

It is worth noting that program behavior and development history was identical on the purchase side, with purchase invoices, payments, and Accounts payable.