Agreed with Saintor and jb's335.
One lab report is pretty meaningless, and I have a very hard time believing that BMW (and so many others) would be recommending such a long interval if a simple oil test proves them wrong. I'm quite confident these engineers know what they are doing on the engines THEY developed.
I'm borderline anal when it comes to taking care of my cars, but will always follow the recommendations of the manufacturer before some random lab test.
And to those of you who are changing oil every 3-5k (and using synthetic presumably) - that's a waste. Quality synthetic oil is fine for well beyond that.