Like blackcat mentioned, it's helpful to look at subtest scores on the WISC - you may see a pattern of relative strengths that fall in line with math ability.
OTOH, MAP is an achievement test, and from your previous posts, your ds has been working up and at least partway through Algebra I outside of school - exposure to Algebra I concepts (and the concepts leading up to it) may be a large part of the reason he is scoring so high on the MAP. This doesn't mean he's *not* extremely talented at math - but I do believe it is possible to some extent to score higher than your IQ on achievement tests when exposure to advanced learning has occurred.
In any event, I'd move forward seeking out the same opportunities in math for your ds that you would have had the WISC results come out at a higher WISC level - as long as your ds is motivated and enjoys math, keep giving him opportunities to move forward and stay challenged
Best wishes,
polarbear
