There seems to be a wide range of mileage reported for the initial (and subsequent) 35d CBS Oil Service: 9k-13k. I wonder what exactly is being measured to cause this large a variation?

It seems unlikely that the CBS is based on the actual properties of the oil in the crankcase, since several of us have done intermediate oil/filter changes. And we seem to be experiencing the same wide range as folks who are doing it "by BMW's book". So it must be based on stuff like: number/length of 'trips', avg mph, temps, etc.

Funf Dreisig