Courtney Mil --
It is perfectly legal to enter an earobatic manoeuvre from that altitude as long as the manoeuvre itself isn't performed at that altitude.
One would imagine that any "manoeuvre" is defined, in a legal and aviation sense, to commence at the instant it is "entered"? For example, "landing" is not just the instant the wheels touch the ground. "Landing" commences at some earlier stage -- somewhere between finals and coming to a standstill. Obviously you cannot be said to be in the "manoeuvre" of landing if you are descending vertically in a spiral dive three metres above the runway, at 190kts. "Landing" is a manoeuvre that requires a sequence of events. I'd suggest that "manoeuvre" includes preparation for entry, entry, and then successful completion. In this case the completion was not successful.