Huh? Wouldn't "where a jump starts" (for counting rotation) be the same as where a jump takes off?
From the point a jump starts, a person can pre-rotate a very different amount, until the jump eventually leaves the ice. On the lutz or flip you might see 0 pre-rotation, but this is becoming very rare. Basically 1/2 turn of pre-rotation (which means the toepick foot for toepick jumps) can be considered "acceptable" for any jump, but people often go past that amount, which is problematic.
Regardless, this isn't talked about at all in the ISU rules, and in practice the callers often just decide an arbitrary takeoff point based upon the direction of the skating foot in the early phase of the jump. They don't take any other important factors into consideration, except the one case of a clear "toe axel" on the toeloop, where the skating foot itself turns all the way to forward. This one case isn't used as a way to count rotation either, it's just an automatic deduction.
Thus, the rule that mandates a deduction for a pre-rotation cheat of a half-turn is exactly what you have just said: "taking off in the opposite direction from what they are defined as."
Sigh, I'll reiterate. Virtually EVERYONE pre-rotates 1/2 turn on the Loop, Salchow, and Toeloop (on the toepick foot). People also commonly pre-rotate 1/2 turn on the Axel and on the toepick foot of the Lutz and Flip.
The ISU rule is nonsensical and thus it is ignored, except in the specific case of turning all the way to forwards with the skating foot of toepick jumps (which nobody actually does). A skater doing a toe-axel doesn't mean they have pre-rotated more in terms of where the jump fully leaves the ice, it's a different form of technique failure. Some people pre-rotate 3/4 of a turn on their toeloops without doing a toe-axel.
First of all, I have plenty of responses that are far more informational than your delusional ones will ever be.
No you don't. You've been proven wrong at every turn when you try to talk specifics in these recent discussions. Instead of giving any real response, you've generally been attempting to paint me as delusional with micro-aggression responses, because you're mad about certain skaters or ideas being challenged and you can't handle it. Please be open to education.