Actually, nothing is trully confirmed by the scans. Keep some things in mind:
First and foremost, DI wasn't taken into account. This has been metioned already.
The scan made some mistakes. Brawl Central even says so. Could this be one of them?
Each shot was taken from the MIDDLE of FD. The general strategy with Sheik is to tilt your opponent to the end of the stage and fair them to death. Fair in and of itself isn't all that powerful, but it's her best KOing move. I doubt the scans took this into account.
Lastly, and most importantly: Sheik will ALWAYS be able to kill. As long as her tilts stay the same and she has at least ONE mediocre (in terms of power) move, Sheik can own. It will only be a matter of how much longer she has to tilt to do so.