Because the money arrives before the remittance advice. It sits in suspense, the customer is chased for an invoice they have already paid, and both sides lose a fortnight to it.
A customer payment is a receipt recorded against the customer and allocated to invoices — in full, in part, or held on account until it is clear what it settles.
Receipts arrive on the bank feed and match by amount, reference and customer. What matches allocates; what does not is held for a person, with the likely candidates suggested.
One transfer covers three invoices and is 40p short. It allocates across all three, the shortfall clears within tolerance, and none of the three shows overdue the next morning.
It will not guess when the reference is meaningless. A payment with no remittance and no clean amount match waits for a person, which is the right outcome.
Allocation clears the invoice, updates the aging report and the customer balance, feeds cash flow actuals, and posts the receipt against the bank account.
Yes, by payment link, and the receipt allocates on settlement.
They sit as a credit on the account, to settle a later invoice or be refunded.
Yes, a value or a percentage below which small differences clear automatically.
Fourteen days, every module, no card. Or half an hour with someone who will run it on your own records and tell you where it does not help.