I purchased a 545i CPO in 2007. I purchased from BMW the 100K "service" contract. At 80K miles on a standard CBS oil service the SA stated they were also changing the transmission pan/filter and refilling as part of the service.
When I stated the lifetime fill, the SA replied with we do what ever the key tells us to do. (plugging the key in the computer at the SA desk).
I have 170K on it now and I am getting ready to do it again, myself.