For the SAT, it is different. I am in the process of trying to get middle kid to prep for the SAT. She took it once this past year, in 10th, just to see how she would do. While her score would get her into the vast majority of colleges in the US, she wants to apply to some very selective schools. All of these schools have very low admit rates, but it would help if she got to 2250+ instead of 2100+.
When you get your SAT scores, they also tell you for each section what the average score upon retaking was for people who made your score. So I know based on my eldest son's reports that people who get a 700 on the SAT math on average get a slightly lower score (maybe 690), and that people who score in the upper 700s lose more (I think about 20-30 points). These statistics underestimate the gains of people who take the SAT in 6th or 7th grade and later in 11th grade. They likely underestimate the score gains of 10th graders by much less.
So empirically, once you score in the 700s on a section, it is hard to improve. Of course you can still try, and the absurd Score Choice option means that the score you *report* will not fall upon retaking, at least for colleges that allow that reporting option.
