RJM - PM me if you feel compelled. Scores matter- The Ivy index is important, and there is no need to dwell on it here. The top LAC's (Williams, Amherst, Swarthmore) are not calculating Ivy index but can be even more demanding - or less if they really want a kid. SAT 2's can help your son demonstrate high proficiency in an environment where HE CHOSES the subject and each test is only an hour. Most importantly, AP exam scores of 4 or 5 prove you can do college work. How did your son do on those tests? The ACT can be a substitute but I think it is rarely a complete game changer. Admissions will convert the ACT score to SAT using a chart you can find on the internet (eg. ACT 32= 1410 SAT). As has been stated before, your son's GPA will be unweighted and reduced to its core, while the strength of his schedule will be "scored" separately, and equally. You can also find data on the odds of doing more than 100pts better on the ACT than the SAT. As I recall, the odds are long but it is possible. Bottom line: I think you can largely overcome the SAT score with a strong list of AP's given succesfully AP exams(4s and 5s only), super strong SAT 2 scores in Math and English plus a strong showing on the ACT. This was my own son's strategy and it worked well.