Timing off when adding CC to a video

I'm attempting to add Closed Captioning to a video file in a project, but the timing of the video playing is not consistent after pressing the play button after pressing the pause button and then starting the file again.

In the image below I have a lot of captioning already added, and when I created marker 71, I had to backup the video a little bit to be sure that the timing was correct. When I pressed play, which should have been synced up with "You will be asked to participate" from the captioning, the audio and video started a few seconds prior to the point which the marker was added.

I've been going through the file in both Captivate and Audition and I'm seeing that most of the markers I've added are significantly behind where they really should be.

I don't know if this is related, but when I'm attempting to time the appearance of objects on the stage when there is video on the slide, that the video always starts a few seconds after it really should.

Any thoughts?

EDIT: When I reached the end of the video there was nothing playing for about 6-8 seconds. Going back through the file now to manually adjust the markers I got to the end of the file and audio/video ran all the way to the end.