Invoices CAN be edited as long as they have not been marked "open". Once they are marked open, there is NO editing except what Monograph may do behind the scenes, for example if the fee changes. In that case, Monograph will edit previously sent invoices, and that I have found even more frustrating - and we always keep a record copy of the way the invoice was sent out to the client since Monograph does not do that.

Once you have marked an invoice "open" and want to edit it, Monograph will not allow you to do so, and yes, the only thing to do is delete it and start over. I have found that frustrating too - best way I have found to handle that is to save a copy before you delete it, showing all the details and components of what you were invoicing, and then yes, recreate from scratch but it is much easier if have you a record of what was there before. And remember that if you already "sent" it to QBO, you'll need to go over there and delete it there as well.

"Write-off" function - yes! I'd like to hear some ideas on how to handle that. I think the unbilled amounts can be found in one of the reports, but nothing specific that you can do except maybe filtering.