Like how we have a check box in Sales Invoice form to Hide Due Date which when checked removes the OVERDUE stamp from the Sales Invoice, similarly can we have another check box to hide the Paid In Full stamp also. Sometimes what happens is that the customer pays 100% of the amount as advance before the Sales Invoice is generated. So when the invoice is generated, it comes with the Paid in Full stamp at the bottom, which the customers object to.
For the time being you can first generate and save the Invoice as PDF before assigning a payment to it. So the customer will not see a paid in full as you have not yet assigned the payment to the invoice.
Then our operations differ. We first generate an Invoice, at that stage no receipt (purchase invoice) or payment (sales invoice) has been assigned. We need to view the invoice and click on New Payment or New Receipt (see example screenshots for sales invoice below). Curious about your workflow.
We would have to click on new receipt on below invoice to assign a receipt to it.