Keep in mind that you have two score instability factors here: age six scores are not highly stable, and the RIAS is not a comprehensive cognitive instrument, thus more prone to being thrown off one way or the other.
But assuming all the scores are reliable, valid, and representative of something real:
PSI should not be a big factor in the NIX. What were his strengths and weaknesses in the PRI? Not all of the PRI skill types are covered in the NIX. If his strengths were not assessed in the NIX, odd things like this could happen rather easily.
BTW, was he re-evaluated at age 9? Five years is a long time to go between eligibility re-evaluations.
Glad to hear he's doing well where it actually counts. Especially with the organization, which is often a huge obstacle to successful acceleration, especially for 2e. And I join you in IQ test geek-dom.
