That makes sense.
The documentation doesn't really clear up what frames refer to when used on a Tween instance outside of a Timeline, leaving me with a couple questions. Is each frame then referring to a requestAnimationFrame callback? Will the timeScale property still work?
While I haven't the moment to play with your demo, if exportRoot() requires extra code to tell it to stop on a scroll start then I'm afraid that is currently unavailable in iOS as, unlike desktop webkit, the onscroll method seems to only fire at the end of a scroll.