More standardized testing worth the effort for current junior?

Agree with @tdy123 and there is empirical data to prove this. See the following link to Brown admissions who breaks out standard test scores and admissions rates in pretty good detail and note how admissions rates ratchet up as scores increase. https://www.brown.edu/admission/undergraduate/explore/admission-facts I would think the same pattern holds true for all the highly selectives.

A 1520 does put your daughter solidly in the running, but since she is only a junior, taking it one more time, maybe right after the summer when she has more time to prep seems worth it to me. I would have her take the SAT since Yale superscores the SAT. I would not have her take any more SAT2’s unless she is considering schools like Georgetown that recommend 3 SAT2’s. Yale only recommends 2, and she has more than adequate scores in the 2 she took. She can better use the time to prep for the SAT, her schoolwork, EC’s or just having fun.