Billing

Is there a way to change invoice formats in billing... contract-based invoices?

We do this when we print a "draft" to send to the engineer for approval before printing on the official documents. I would like to use the p-pb detail with retainage for the draft and then go back to  the original AIA forms when approved.

The only thing I can find is to change each line item in contracts but these jobs have around 200 items so its a pita to change them and then change them back.

Thanks for any help