Well in fact I think it was more complex than a simple zoom problem, I need to remake all the new 4:3 cropping. But now it will be a lot faster and easier for me to do it. I worked in such a wrong way I can't believe it!
The most obvious exemple is the Lucasfilm logo :
Before:
After correction (do not pay attention to the color tint):
I know this problem apparently do not shows too much in the test DVD, but once you know it's there, it is distracting.
I still hope in a two weeks release anyway.