TMPGEnc dvd author mpgs shrinking

Ok this is driving me crazy,Im experienced with dvd captures.encoding etc but i have recently used FAB DVDecryptor to strip a dvd and put in to my hard drive as normal.
Its a TV show dvd with 6 x 25min episodes that I intended to burn on 2 DVD R discs as normal.

I made the 25min mpgs and using DVD Author 1.6 I built a menu then encoded to DVD for burning.However 2 of these 25 min episodes were only 15 mins on the finished file.
I tried again making sure the mpgs were in fact 25 mins long and tried to make my DVD file for burning.same result.

You ripped them to hdd before, so DVD Author authored them for you.
Make sure those 2 eps were ripped correctly.