Filesize after compression

I have a problem that never occure before.
I live in holland and I did a backup;) of my Atlantis disney movie.
I used Dvd2One v1.1.3 first to backup the whole movie like I always do. I got an output of 4.52 Gigs.
I had that a couple of times before, my target was 4472 output
way to big to fit a dvd-r.
So I selcted my target to 4400 but then my output became 4.53 Gigs.
I trew my computer trough the wall and after buying a new one
I started using Dvd2One v1.20(with good hopes)
The output now is 4.46 Gigs even if I select a target of like 1000.
With constant compression I got it to 4.37, but the quality was to cry about. Losts of blocks and sucky quality.

What am I doing wrong???