WOW, first have that started filming?
I think this raises more questions than answers, but it seems like just shooting 25P and going a 25 to 24P would be the smartest thing to do, DV filmmakers did that for years before a true 24P came out and then is this conversion built into FCP.
The thing to do is to fine out exactly what this hack is doing, it may actually for going to the P2 card as true 24P. In the end there many not be a huge problem, just a lot of craziness.
The last question would be why not just use the NTSC HVX to record both the sound and the picture?