User is trying to bill a project using a Percent Complete value in the Invoice Batch screen, but updating the % Complete field does not affect the Net Bill amount.
This happens if you have already billed the project to an amount which is greater than or equal to the % Complete value. In other words, if you've already billed this percentage of the contract amount on the project, you will have to use a higher percentage in order to affect the Net Bill amount. Check CORE Help Center for details.