That's a good way to prove it, theoretically at least
I think she's probably speeding anywhere between +8-12% though, this would suggest 20%+ which is obviously really high... Maybe I'm not thinking about this correctly

Edit: Looking at it again, you stop for a frame before your 2nd swing and she starts her 9th swing when you finish your 7th one, so it's closer to 8 swings which puts it more in line with the % that I think she's using

Either way, that makes it pretty obvious she isn't capped at the same framerate as the rest of us
The fact that she's gone 6+ months doing this is a shame