I hope I didn't squelch anyone's opinion... when I get on my soap box you can't shut me up... this has not served me well at times
I talked to my friend who owns the Trans shops about the bmw long life/ lifetime trans fluid deal.
If a BMW comes to him and the car's trans is functioning the way it should regardless of the miles he will do the fluid change. If it's newer under 50,000 miles he does the power flush. if it's a higher than 50,000 then he does the pan drop, drain and fill 3 times. On the next change they do the power flush in both scenarios. he does the filters at the same time.
In transmissions that he has fluid changed, remember no apparent defects in the trans he has never had a failure related to the fluid change. He said he does not believe that any machine that reaches the high temps of a transmission doesn't need it's fluid changed. He also said that in transmissions that he maintains for people it's nothing to get 200K+ out of a transmission.
He basically doesn't buy it, and he said all transmissions should be maintained with change intervals.
This doesn't settle anything but, an expert has weighed in.