frame rate weirdness

I'm working with an animator overseas. For preview renders, he sends me Sorenson 3 movies (the finals will be in something like 10bit). I use QT to convert the Sorenson movies to DV before putting them in my timeline.

Although I ask for 23.98, sometimes his renders arrive at 24 fps. I don't know if this is a problem with Sorenson 3 or a mistake on his part.

When I convert them to DV, I set the frame rate for 23.98. But when I open the resulting QT and get info on it, it says it's 24 fps.

I put it in the FCP project and the Vid Rate shows 24 fps. But when I drop it into a 23.98 timeline, it plays without rendering!

What's going on?

Do QT and FCP use 24 as short-hand for 23.98? Or is there another gremlin at work?

Thanks.