That is definitely a flaw, yes. It's a rather glaring one, and I wonder how it went unnoticed given that you can clearly see the TV camera on the rover so it obviously isn't being used to record this footage! Even if the author didn't know they systems by sight, it's a fundamental part of any rigorous study to properly identify the source of the material you're working from. How often have we had that argument with HBs here? It's not hard to find that information and it should have been step 1 of the whole process.
There are other questionable aspects too, such as trying to measure the position of a cloud of dust particles, which is only visible when enough grains gather in the same spot in space to be resolved by the film camera. I don't think you can assume the track of a visible cloud of particles can be treated as a single entity under ballistic conditions.
All of which means that, while the error in the time factor of the calculation is not enough to change the conclusion from lunar gravity to Earth gravity, there is a fundamental flaw in it which means it's hard to use this to defend the reality of Apollo while maintaining arguments about the provenance of source materials as a defence against HB claims.
