If you have a frame count of 24 fr's in FCP and you export it out to QT file.
In motion the frame count will be 24 frame.
If you put it into Photoshop the frame count will be 23 frame. Photoshop has a 0 (zero) frame.
when I export the video out of Photoshop. It truncates the video by one frame. It ia now 23 frames.