Yes, I am sure that there is PG lumping. I typically try to use the term HG+ to indicate that there are many layers beyond MG.
The issue of graduated college by 12, though, while related, is perhaps not a fair marker of the extreme PG. The kids who do that are doing it because their drive and their field of interest happen to match well with what college and grad school have to offer and the family is able geographically to meet that need. Many kids who may be equally smart may not have personalities to fit well with college at an early age, or whose gifts are fed without the commitment to college, or have parents that cannot or chose not to put there kid in a college. So even if there are only 7 (and this seems low) kids who are in college or grad school full time by 11, there are probably at least another 21 who are just as smart but 'solving" the problem a different way.
