Originally Posted by carve
There is only one page in that thread. You can't view the PDF unless you're a member. Why don't you repost it here?
The oil condition sensor measures the conductivity of the oil. That may tell you how much water is in the oil, but not much else. Go ahead and change your oil on your own and then tell me if the computer lengthens the time until it says you're due for your next change (hint: it doesn't!)
Furthermore, The N54 is under a lot more stress than NA engines, and the tight tolerences in turbos are very demanding on oil quality. Oil that may still be "good enough" for an NA engine is not necessarily good enough for the N54.
Have you considered that the oil condition sensor has more than one variable- ie time, mileage and condition sensors? Would it make sense that BMW would say, let's just measure the conductivity of the oil, and if that's good, let's tell owners the oil is fine... we don't need to worry about mileage and time?