It's hilarious that sites that purport to calculate IQ scores from other test scores generally don't mention error in estimation in either kind of test, nor do they mention regression to the mean.
Yeah, it's quite a sketchy methodology. I know his stats are false because I come out with a 150 IQ, which I definitely do not have. Plus, Mensa doesn't consider the modern SAT or GRE to correlate with IQ.