I think WRV has used the same mechanical units for the bedroom slides for many model years. In my 2001 driver side, slide, if I don't watch close it appears the slide will go past where it should stop on the bottom, resulting in the top cocked inward. By retracting just a little bit and watching the wood molding around the side top to bottom it will line up with the inside of the coach skin. Sometimes I miss and have to go in and out a couple time to get it lined up.
If yours is lined up on the inside and the outside is an 1" different, then I don't know what to tell you. Other than it wouldn't be the first I've found that WRV can't read a ruler.
D & D Rich
Great Salt Lake Route
2004 Alpine 40 FDTS