Have you looked at other Aerolite 294 models? That seems to me the quickest way to determine whether yours is off or it is "by design" Dealers will say most anything to get on to the next sale...
Very good point. Had a "slide issue" with my Aerolite. Still under warranty, the dealer service manager said it was within tolerance. But got worse over the next year. Over the next 2-1/2 years I have run into two others with the same model and year who had the same slide issue.
Be nice to get something in writing stating your RV has had a slide issue right off the bat.