Even if the score with the extended norms or even without them is inflated somewhat for whatever reason (his age tends to be one where kids get higher scores on this test [I hadn't heard that for the WISC, but you mention it and I have heard that about some tests], Flynn Effect, whatever), he is clearly gifted. He is also clearly bored. Even if he wasn't a PG kid and "only" a HG kid or even in some instances a MG kid with a lot of drive, none of those would say, 'some enrichment is enough, he doesn't need acceleration.'
I have a kiddo who is HG, but not DYS, and she really needed a skip. It wasn't just something that worked fine, it was something that, without it, school would have been such a poor fit that I'm not sure she'd still be in ps now. She was also very young for grade pre-skip. It really isn't just older for grade gifted kids or PG kids who need something more.
All of what you say in your last post about verbal precision, memory and processing would apply to my skipped kid as well except for the last piece. She is extremely precise in her speech; heck, she even punctuates and capitalizes her text messages precisely and correctly! She has an amazing memory. What she does not have is high processing speed. None of that means that the scores obtained by kids with those strengths mean less or are less indicative of the need for a skip.
Also, having used EPGY with my younger child for a bit when she was in elementary and improperly placed for math so we decided to do a little supplementation, I can say that it is a good program, but I doubt that giving him EPGY in lieu of the regular math curriculum will be sufficient to overcome an overall inappropriate grade placement.
My oldest, the skipped one, is not less well adjusted or happy post skip. If anything, we probably waited too long to do it (she skipped 5th) b/c she had already reached a point where she clearly didn't fit with her peers and was starting to deal with one of two things as a result: bullying or the other kids treating her like some kind of prodigy. Socially, the fit has been much, much better post-skip and dd is actually considerably happier and more engaged as a result. She was becoming a bit of a slacker in 4th grade. Not that we don't see procrastination still, but it isn't nearly as bad as it was.
