I lost points on the SAT for mixing up 2 pi r and pi r^2 - left out the 2 for the former. (That's the one that stands out as a duh, I knew better, one - I forget what else I missed.) There were also a LOT of analogies. I've read that those have been removed, I dunno how the math section is, but both of those were much more "knowing things" than innate intelligence. Grades tend to require both "knowing things" and longer-term discipline; I could see where that would be advantageous.

Grades have a disadvantage of A's being way too common, though - no resolution at the top of the scale.