How to Auto Upload In Advance Invoices while utilizing the Distributions tab

Summary: A year ago we entered an SR asking for assistance with how to upload an In Advance invoice. They can back with we needed to clear our Distributions tab for this to be successful. That did work for the time. However fast forward and we've had to remove some default revenue coding and now when we are uploading we get an error there is no Revenue coding. When I think about all this I don't understand why we can't upload an In Advance Invoice while utilizing the distributions tab.

Content (required): We've removed the default revenue coding from some of our transactions as our AR staff is having difficulty changing some of the values which results in reclasses. Now when they upload an in advance invoice they receive an error for missing revenue string. We just don't understand why we can't utilize the upload spreadsheet while entering in the specific revenue coding.