You would still have a perfect score after the question was annulled. It's just the difference between getting (for example) 33 out of 33 questions correct, or 34 out of 34 questions correct.
Well what's interesting about it is that a perfect score would be unaffected, but anything less would be affected because wrong answers are now weighted more heavily than before.
Although I'm not sure how the SAT assigns the scores - I don't think it's as simple as a percentage correct (otherwise the score would simply be out of 100), and that there is some kind of normalization they do? Can't remember... and it might have been different then anyway.
