I appreciate the details a lot, @3axis.
Currently, we're unable to display the progress billing on the invoice. However, we can show the current percentage of the whole invoice as you can see in the sales form.
Also, the option to show progress on line items selected for the invoice is for customer's viewing of the current rate on the line item that they have to pay for. That's why we're unable to see it when creating the invoice.
In case you wanted to see information about the progress of billing on the invoice, you can pull up the Estimates & Progress Invoicing Summary by Customer report.
There you can customize it, view the amount that had been invoiced, and check the current balance of the estimate.
Here's how to pull up the report:
- Go to the Reports menu.
- In the Search box, type "Estimate" and then select Estimates & Progress Invoicing Summary by Customer report.
- Click Customize and then change the Report period to All Dates.
- Select Filter.
- In the Customer drop-down list, check the box beside the client's name.
- Then hit Run report.
I've added an article as your reference for more details about progress invoicing in QBO: Set up and send progress invoices in QuickBooks Online.
Also, you can send this report to your customer by clicking the Email icon just beside the Printer icon on the statement.
Feel free to drop a comment below if you need further assistance. I'm always around to help. Take care!
