I'll take a look at my WISC-V manual for any correlation data with the KBIT-2; that would be pretty much the only place to find it. The KBIT-2 manual would have correlation data for the WISC-IV, but that's probably not the test you're referencing.
And I would agree with Priiak that it's not the title or the years of certification, necessarily. Especially when you are talking about a relatively new edition of a test (WISC-V has only been out for about 1.5 years), with some substantive changes over past editions. Actually, when you go to a big name children's hospital or research university for a neuropsych eval, the actual testing is nearly always conducted by a pre or postdoctoral intern, or master's level psych technicians.
If the intern is an actual intern (post-master's), and not a first-year pre-practicum student, he has probably given the WISC-V about as many times as the school psych has. It is true that he is less likely to have extensive experience with giftedness (though that is also not necessarily the case), but presumably his mentor will support him with interpretation. (I think I had more experience with giftedness, especially at the PG-level, than many of my field supervisors.)
School psych is an area that has a fair number of experienced educators pursuing additional certification or re-specialization. This is how situations like those Priiak described can occur. A not insubstantial fraction of school psych trainees have previous experience as teachers, school counselors, or other mental health providers.
