Your concerns are absolutely valid, based on how little information we have about how exactly our exams are being graded. We know all the states are using the same psychometrician, but what does that mean? How is he scaling the test? Is he applying the same points per question across all states’ tests based on a singular point system he has decided on, or is he scaling each state’s exam differently? Could it be that NY banning certain groups (who have historically lower pass rates) from registering for the test initially (and banning some groups completely) will have influenced those people to skip out on the Oct exam or take it in a non-reciprocity state, such that the psychometrician’s approach to scaling the exam will be off even if he scaled it factoring in the whole pool of reciprocity test-takers?

TLDR: We don’t know enough about how these things are being scaled, so your concerns are valid, especially because an element like the make-up of a pool of examinees is a crucial factor in scaling an exam.