The off-centre lenses come from the grey and black markets. Such lenses are also available from Canon and other brands. The specimens from Sony Switzerland and Sony Germany are not rejects. My copy from Sony Switzerland is in tip-top condition. Direct imports from Digitec are also fine; these come from Sony Japan, Thailand or Hong Kong.

1. why from Digitec? -> manufacturer's warranty, there is an adjustment.
2. Have you read this in German forums? Products intended for Switzerland are subject to a higher quality control... at least that's my observation. (Or I was simply lucky when I bought the lenses).