I previously took the old SAT and scored a 2200, but I wanted to get a higher score on the math section of the SAT since all of my errors were made on the "easy" level questions, which is frustrating and is probably the cause of a lot of careless errors. I would really like to take 2 SATs so that I'll have the ability to super score my new SAT, but if I need to take the Math II subject test then I'll only have one shot at the new SAT at any colleges where I'll be applying Early Action/ Early Decision (I am currently a junior).
I took the SAT Subject tests in May (thinking it would be perfect to take them right after the info was fresh in my head after AP Tests), but I didn't take any mathematics Subject tests. I've now been finding that many of the schools where I'll be applying suggest "A Math SAT II and one other". I'm wondering just how important the Math II is to schools who suggest their applicants take it (I'm not applying to any engineering schools but I've found that some liberal arts schools like Davidson suggest it), and whether or not it is worth it to miss out on a second chance at the SAT.
The answer to this question depends on your SAT Math score, your GPA, the schools you're applying to (and their average SAT Math scores), and to a lesser extent on how well you do on the SAT Subject Tests you just took. A higher current SAT Math score compared to the average score of the school you're applying to (and a higher GPA) would lead me to recommend taking the SAT Math Subject Test, while a lower current SAT Math score compared to the average score of the school you're applying to (and a lower or average GPA) would make me recommend re-taking the SAT instead.
For the sake of argument, let's say that your SAT score of 2200 breaks down into 660/780/760 on the old SAT Math/Reading/Writing sections, and that you're looking to apply to Davidson early decision, round 1 (the second round has a deadline of January 2nd, so you'd actually have another test date to take advantage of and would be able to both take the SAT Math Subject test and retake the regular SAT and increase your Math score).
A 2200 score on the old SAT is just a little below 2240, which is the 75th percentile score for Davidson students (meaning 75% of admitted students got at or below that score). This puts you pretty solidly in the "safe zone" for your total SAT score. However, if you take a closer look, you'll see that 25% of admitted Davidson students had an SAT Math score of 650 (or below), while 75% had an SAT Math score of 740 or below. Your (hypothetical) 660 on SAT Math just barely falls into that range, so this is where your GPA and your other SAT Subject test scores come in.
If you have an average GPA and high SAT Subject Test scores, then it wouldn't be a bad idea to re-take the SAT. While it's unlikely there will be formal superscoring between the old and new SATs, admissions officers are still going to look at your scores for both tests if you submit them; because the new SAT Math section actually involves some more advanced math than the old SAT, a higher score on the new SAT Math might be even more impressive. With a higher GPA and lower SAT Subject Test scores, I'd probably recommend taking the SAT Math Subject Test (and excelling on it) instead (since Davidson recommends the submission of 2 SAT Subject test scores, and you want to put your best foot forward in that area as well).
In general, though, when it comes to college admissions submitting SAT scores is required, while submitting SAT Subject Test scores is more optional; if you have to choose between the two, it's better to increase your SAT Math score to be above the average student's score at your target schools than to try for a high SAT Math Subject Test score.