I have a 2009 328xdrive.
You can find my UOA in the UOA section, on the dealership oil that I run 9000 miles for 16 months with no ill effect. I got quite some short trips and two winters on it.
That may help you decide what to do.
As of now, I have GC 0w-30 in the car for about 13 months, and it seems the oil got more loose in the last few months, so it is going to be at the end of its useful life in a few months... but this time, I am close to 10.000 miles already, so I may change it soon (within a month or so).