Could it be that you have set the program for 25fps but then exported at about 30fps?
Check under File, Setup, Program, Options tab. If you have it set to PAL (25fps) but you want NTSC, then change it.
When you export, check the settings - presets and Frame rate. 29.97 is for NTSC, 25 is for PAL.
HTH
Hi when I tried it at 720 it worked fine,then closed the program & restarted & then put in 1920 as could not select it anymore in quicktime,and then the time was accurate, had 25fps for pal. but maybe its buggy with quicktime?? but results are good :)