I am also saying that your hands don't move where you try to move them- so it's very likely that he's tried to imagine and feel his hands moving on "his ideal" plane- say turned shoulder- but he is well above it at the top.
I am not "tying" 1) the hands closer to address to 2) any issues of pivot power.
I'm actually thinking that it would be harder to take the hands back flatter with the hands stretched out so far at address (couple of ways to look at that - so I might not have that correct - however as I mentioned - the hands closer to the body at address would allow for a better shoulder alignment and therefore set him up to take it back more on plane i.e. flatter.
All of my comments would apply to swinging or hitting.
However, really a very nice movement- that he's going to continually improve on and get better and better.
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Life Goal- Developing a new theory of movement based on Brain Science
Interests - Dabbling with insanity
Hobbies- Creating Quality