I don’t see the logic in why a school would Superscore if the objective was to form the best assessment of the candidates. First, their is some value in seeing the mix/range of scores a candidate submits and there is the potential for some insight. However, for a lot of examples, there probably isn’t too much insight and it would be squinting at details. So if the objective was then to simply the issue and arrive at one score for a candidate, they should AVERAGE the subscores for each section for a candidate rather than taking the highest score for each section. That would be the most informative score for a candidate and the appropriate score to be comparing against other candidates that only submit ONE test score. By Superscoring, it incentivizes candidates to take the test multiple times because almost certainly their Superscore will be higher than any of the individual test scores.
However, the only rationale I can see for schools to Superscore is that it will create some degree of artificial boost to level of the average or median SSAT score they report for accepted students to their school. I’m not sure how significant an upward boost it is, but it is something and it’s artificial. If every candidate submitted 3-4 sets of SSAT scores and schools Superscore, it would create immediate “grade inflation” for SSAT scores.