Vob to Xvid Strange sync problem

Ok I asked this awhile ago

Since then I have tried anydvd dvd43(Not at the same time)
And many other programs including dvdfab dvd2avi and gordian knot

Dvd decrypter show no offset on the sound track nor does Demux Ac3 and where as I can make a copy of the Dvd which behaves normally if I try to convert it to a xvid I get an 1700ms out of sync I know I can compensate this in virtualdub mod and have done so but I would love to know the cause
I have noticed that dvd decrypter place an asterrisk next to a cell and unticks it warning of structure protection but the length of the cell does not match the required offset