Wow, the highest I've ever gotten in MGMAT cats was 690 with my other 2 scores being 640 and 650.
My last two GMATpreps were 740 and 760.
You are right. Most people do better on the GMATprep than the MGMAT, a few get the same score, but you're the first I've ever seen get higher on the MGMAT.
That's really impressive actually!
GMAT Club Premium Membership - big benefits and savings