If I understood you correctly it sounds like you have 4-Bank tab stock loaded in your paper tray but you have the paper tray setup as 3-Bank tab stock because you, "...have to change the number from 3 to 4" when you go to print. If that isn't the case, then you could try setting Tray 5 up as the pre-cut tabs and send the print job with auto paper select or auto tray select and see if that works.
When trying to print Tabs using the Xerox Template I keep getting a held for resources error. I've loaded the 4-Bank Tabs into Bypass Tray 5, and the machine sees them and confirms them as the stock in 5. I go to print, choose the Pre-Cut Tabs option, change the number from 3 to 4. Then the job just sits in the queue and is held for resources. I can't figure this out, any help out there?