VideoReDo + 3 seconds

it does a pretty good job joining mpgs! I love that aspect, I tried several others and their final mpg were out of time, this one produces good joined mpgs with the right time and frame in place, but what bugs me is that at the end of the movie, says like 1:25 but the video stops at 1:21-22, now after examination I discovered that there is no missing video; and that those 3sec extra is probably added for “¿some reason?”.
I want to know if there is a way to correct that, probably reindex it? and what is it about too.