I have talk to a friend (works as a bmw tech) and also the service mgr at Turner Motors....both said not to touch the tranny fluid...unless there's a problem with the mech seal
I only have 50000 miles after 7 years so I'm going to leave it alone, by the time I hit 100k miles....car is around 14 years old. let me know how it works out for you.
2006 325xi (Sold)
2014 M235I (Current)
2015 428xi Gran Coupe (STB)