I think it depends on what your options are. For example, if you are full pay and have a highly ranked public high school or even day school, and if the BS did not have any compelling ECs, I might wonder if the high achievers at the BS were really going to offer more than the high achievers at the local public school. Is it worth it, all things considered?
At the other end of the spectrum, let’s say one needed full FA, had no particular hooks or compelling EC’s, was a good student but had unusually strong SSATs. Then maybe a school with lower median SSATs would be a good strategy to get in and get FA, perhaps.
Outside of those two extremes, my gut feel is that +/-10 vs the median SSAT percentile for any given school is probably the sweet spot. It is probably false precision to suggest that the SSATs are terribly meaningful on a more granular level than that.