Or rather, I should specify that it'll take 55/45 frames for them to recover out of that state because of 46P recovering at 24 frames. The amount of recover it takes for someone out of that bounce rope while back turned will vary per character, per move.
It works because 46P recovers in 24 frames. It takes the opponent 55 frames to recover to a neutral state if they didn't stagger. And 45 frames if they staggered at fastest, from their back turned state. So yes, it's guaranteed as long as you are behind the opponent. You end up to their side(s) or in front of them, then no.
