"Long Jump" on a Throw In?

[Freddy]

I'm happy to call the long-jumper "legal" on a designated spot throw-in, except for this one requirement, expressed in two places, that sticks in my mind:
"The thrower must keep one foot on or over the spot until the ball is released" (4-42-6 NOTE). And, "The thrower shall not leave the designated throw-in spot until the ball has been released on a throw-in pass" (7-6-3 and 9-2-1). The phrase "You are where you were 'til you get where you're going" seems not to apply when the above requirement restricts it, with the designated spot, of course, not extending past the boundary line.
The NOTE after 9-2-10 ("The thrower may penetrate the plane provided he/she doesn not touch the inbounds area..." doesn't, I'm thinking, dismiss the above requirement, either.
Agree?

Important to me cuz "Throw-Ins" is the topic of our next pre-season rules meeting.

Thanx for your responses, the ones that dwell on what's in the book.