There is a subtle, but important, difference between “start invoice” and “overwrite invoice”. Start invoice means that you currently have no line items in your invoice and you would like to transfer line items from production over to an invoice to progress the job.
The overwrite invoice option appears when you already have line items in your invoice. It allows you to replace line items that are in your invoice already with line items from production.
So, if you see overwrite invoice instead of start invoice in the hamburger menu, it means that your invoice already has line items in it and you are about to overwrite those existing items in your invoice with line items from your production phase. You must be sure that overwriting is what you want to do because you cannot revert back to what you had in your invoice once you overwrite.
Key words: overwrite, start invoice, invoice, change invoice, change estimate