I appreciate that. We did consider that he needed to go "back to basics". That being said, I know plenty of very good skaters who have terrible core strength, so, that's not it. Fliexibility?.... possibly. He has good flexibility, especially at the ankles where most of this would be relevant. Still, it's possible he lost some flexibility with rapid growth in the last month or two. Looking at all options now. I am thinking 1) OTG suggestion that it is a blade alignment issue. It started shortly after he went to a new pair of makos. Everything else was the same except the length of the steel. It makes logical sense that misalignment could be the culprit. But... 2) Since he has more speed now due to the length of steel. He may simply need to work on the basics of his turns at speed. He has VERY GOOD basics though, so, that's a hard one to swallow.
Since many elite skaters are on shallower hollows (I'm not elite, but on 3/4 myself), I didn't think that was the explanation, but that's what he has in his head. Oh well....
Anyway, no clear consensus on this, so, we'll just need to try some things in a systematic way. No easy fix, I don't think. Heck, he may simply "grow out of it" as he gets used to his new found speed.
Thanks for the suggestions.