just watch the dvd before ripping and make note of the titles numbers for each of the 4 episodes - use the display/info button on your player.

i've seen a similar phenonemon with X files series, somethimes there are more titles that episodes & that's because sometimes there are 2 versions of a tiltle - one with a deleted scene put back in & one without. check the times of each title + the times of the smaller ttles & do the math - you may find this is what's happening.

the double length title will be for viewing a double length episode & will be a duplicate of 2 of the other titles - again you can confirm this by adding the times.