this happens alot. Its seems that AA has been breaking up the inventory more and more. Happens across the board, not just at the W level. For example a flight that is shown as a through flight with a stop in STL (ex: TUL-STL-DCA) will sometimes show V1 from TUL-DCA but V5 from TUL-STL and V0 from STL-DCA.
YMMV.
Cheers.