The only way to accomplish this at the moment in QuickFile is to create a new invoice each time.
Perhaps a way to solve this would be to convert the estimate, tweak it before converting and create an invoice. Then duplicate the estimate and repeat the process.
Perhaps the API would be something worth looking at?
I feared this may be the case. However duplicating the estimate it would not be showing true story as it would show more work quoted than it really is. Other disadvantages would be:
invoices will not be linked to original, accepted Estimate
the customer would be seeing same work quoted several times (and requiring acceptance maybe?)
In some cases we issue up to 7 or even more invoices, depending on how large the work actually is.
Is there a chance to be included as a development? I think it is very much like the recurring invoices, just that invoices would be issued manually.
The most important bit is they would all relate and link to the main Estimate.
It would just make things so much easier for everyone (including Client) to reconcile total amount invoiced against an agreed Estimate.