Solidworks doesn't maintain surface consistency across versions. I don't understand why they can't keep a versioning system within the model to keep the part's topology the same across updates. I haven't seen this in a while and thought that they'd addressed the problem (it was a problem particulary with lofted surfaces early on) and am surprised to see it with a swept surface. It doesn't necessarily bother me that the surface would deviate from the centerline spline, although .0003" seems like a lot. The problem is the discrepancy between versions. We prototyped this a year and a half ago, and are now cutting the production tooling. The prototypes were created in swx2012, but we've since transitioned to swx2013 and that's where the production tooling was created. So now we have a discrepancy between our production and prototype drawings (we're still cutting to the original prototype of course).
We created the model using a swept surface in swx 2012. It uses a spline as a centerline. The resulting surface intersects the spline 100% in 2012, but deviates by .0003 in Solidworks 2013:
After a cntrl Q(!) in deviates by .0002:
Kind of a terrible situation since all the solutions are messy...