I agree with Beavs, the quality of YouTube combined with the fact that these are very preliminary clips is probably the reason why the timing appears off in the warm-up. Don't expect the actual workout to be timed to the music though. It's been explained several times that that is practically impossible with this type of weight work. Especially when going heavy and maintaining proper form are your focus, not keeping time to music. They said early on that they would do their best to match the reps as much as they could, but that they were going more for motivation with the music and NOT timing.