Well BMW did apparently change the bearings after 10/2008.
A few people were affected by this and most of them were 2008 cars, including mine. I also had very bad main bearings when I tore my engine apart due to warranty issues that I worked myself through myself.
If your is a 2010 car and it is confirmed the main bearings issue, then I really dont know what the fuck is going on at BMW. It seems they cant get things right. Even the N55 engine now still has the same HPFP problem and even after the S54 bearing problems, they still have it though in much less numbers. This should not be happening AT ALL!