[setr]

It might also be because the system is not actually consistent or well-defined. They might, say, depend primarily on reviewer judgement, and can measure reviewer correctness on hit/miss student ratios for those admitted, while not actually encoding it in strict law.

Exposing this however would inevitably require that they do, strictly, define their terms and conditions, which may lead to worse outcomes, if its not easy to produce non-gameable rules, or rules that actually match successful reviewer judgement.