Just a thought -- you may want to check the delta angle, the difference between heel and toe height on the PRD 12 and the Mojo you mounted on the ski. I recall that the Mojo actually has a greater delta than the PRD. Different people notice different things, so even if the change is minor, when combined with everything else, it may be noticeable.
I'm also a bit concerned about a shop that relates the tune of a ski simply to how sharp the edges are. How flat are the bases? Did someone rail the ski on the grinder? Is the base edge bevel consistent across the entire running base of the ski?