I was what could (only very charitably) be termed an "indifferent" student throughout high school-- and my GPA showed it. Oh, sure-- I am 'gifted.' I'm HG, in fact. But I had a 2.4 GPA. (Er-- or thereabouts. I'm not sure, but I definitely had a few grades LOWER than "C" on that transcript.)
But still-- every standardized exam I've ever taken I've hit a home run with. The same way that you've reported-- the kind of "WOW!!" performance that seems completely incongruous with the rest of the person everyone knows.
This is me too. I test in the "HG" range, and my grades in school were a direct reflection of my level of interest or lack thereof. I did fine on tests though. In fact, I love taking tests (my competitive side comes out, lol).
