DVDshrink Can`t shrink?

[BeHappy]

I wan backup the DVD Special Extendet edition of "the word of the rings 1,2,3" but on the disk 3 and 4 (whit the specia futers) the dvd shrink can`t shrink more then 51% the video and the dvd is biger by 100-200 mb .First i think that the max video compresion is 50% and the picture in the dvd and the menus are too big and even whit 50% size of the viedo its biger then a DVD+R but on some DVD it compres the size to 35% ?

p.s. i`em using DVD Shrink 3.2