I'm familar with that issue and I know that there are so many reasons why this might happen.
I guess a good value (when everything is gone "to sleep") is significantly lower than 0.1 A.
However, it will take some time to bring everything in sleep mode. IHKA will be one of the last that is put to sleep (not sure... 5-10 minutes).
Well known items that have a problem get to sleep are:
- IHKA
- Central Door lock + power windows
- Radio and amp
- CD player
- ...
- many more
Take a look to:
http://bmw.e-wiesinger.de/#batterie (however, in German. Use google to translate).