@KevinJ of Kansas I did few tests in our SB with the advanced setting (changed it to form B for e.g.) but it does not seem to save the form that way (in the field mapping section I updated another field value to make a change) But anyway, I think what works the best is a scheduled workflow option along-with identification of Invoices to be changed (saved search)--- Probably the quickest...I tried even mass update and it does not provide any option for custom form change..