I can't say this is the gospel truth....just what my son's guidance counselor told us. He calculated my son's AI using his GPA (school does not rank), SATI and 2 SAT 2's (which weren't that great). He then did it using the SATI portion doubled. He says the Ivies take the higher of the two even though you have to submit the SAT 2's for admission. He assured me this is how it's done and they run these numbers all the time for Ivies. (Son's school sends lots of athletes to Ivies).