Your math for comparing SAT scores is off (what is the point of dividing everyone's score by ten?) There have been two main changes in scoring: in 1995 they recentered the scores which in effect increased many peoples' score on the order of 50 points or so (one can convert old scores here: http://2-bit.com/misc/satcalc.html). In 2005, they added a writing section so now your score is out of 2400 instead of 1600. Also, I think you'd want to compare peoples scores based on the current scale which would mean adjusting scores prior to 1995 so that they are recentered and either multiplying by 3/2 for scores before 2005 or discarding the writing portion for everyone.

But many people don't even take the SAT. At least when I was in high school (and likely still today), midwest universities tended to prefer the ACT. Thus, you're essentially looking for people who hit some percentile on national tests, similar to what one would do when applying for MENSA.

Also, as you and others have stated, this isn't really the best way to evaluate people for programming jobs.