Please note that this person's title was "Director of ______" (the summer gifted program at the university in question).
To me that seems like the most annoying part... that the very director of the program doesn't know this!
We had a similar experience with a local summer TAG camp (and a quite expensive one at that). I kept pushing to get her into the 6-8th grade group as opposed to the 3-5th (her age put her in 5th grade). But their response was "well it's for TAG students already so it should be advanced enough." Of course she was bored and had covered most of the work in class (even the dissections).
The difference was during the last day "parent show and tell" I cornered the director of the program and explained my situation. She was very understanding and apologetic and I now have an age exemption on file for future classes. It doesn't help with everything (some of the hosting sites, campuses and such, have their own rules) but it allowed her to join a veterinary visit class for middle schoolers without any fuss.
As for the original topic, I think of DD as PG but technically she may not be. She topped out on the WISC IV, but we didn't go back and do the extended norms (didn't seem worth the cost as we'd learned what we needed to from the results we had). I think the names of the levels are less important than the acknowledgement that there are different levels (just as there are different levels of intellectual disability that can affect plans and accommodations).
One of the first things the tester asked in explaining DD's scores was "do you understand how standard deviation works?" We did. You'd expect people in the field to as well.
