generally directors comments in the audio options will take up anywhere from 2-5% of the total quality.
I know me personally, i choose to remove all that since I wont listen to it and removing it improves video quality.
ALSO, one VERY BIG thing. Some of the video titles (usually the first 2-4) may be the same length in time (movie length).
So for example: the top two LOOk the same, same # of chapters, same time frame, etc.
And on the video preview you see no difference in the two. And removing one DOESNT improve video quality. this is why.....
The first or second one is the "Directors COmments" video files. Some DVDs keep movie and movie audio on one file section and the directors comments and directors comments audio on another.
if you removed the wrong one or left both on there it may simply have two video files.
try playing around with the video and audio options first.
as for the movie. I have a 100% working copy with directors comments properly removed.
hope my .02 helps