As for LOG, I think the thing to remember when you hit DYS qualifying scores is that you are dealing with a kid who may have exceptionally different needs that schools are not used to seeing. In our experience with our DS in the regular local schools, the biggest problem turned out to be pacing. So even with a grade skip, things still weren't quite enough. We transferred him to an accelerated program for HG kids, which is fitting really well now after the grade skip. Our DS7 sounds a lot like yours (mine thinks that school is a waste of time when he could be home playing Minecraft). So what am I trying to say? I guess I'm trying to say welcome to a new normalcy.
The 21-something, if it means something in the 210s, is a high score. With the new 2011 MAP norms, it probably isn't as impressive as it would have been with the 2008 norms, but still very high. Is this math or reading, by the way? Here are some good links to see what those scores mean in terms of what your son would be ready for. You can compare these to your son's curriculum, or ask your son's teachers if he'll be learning things at that level.
http://www.powayusd.com/projects/edtechcentral/lladder/Default.aspAnother good thing to do with MAP scores is to ask if there are kids with similar scores in the classes that your DS is taking. So if he's accelerated in math one or two years, will he be in good company?
