I read this post with interest, and with at first, some degree of sympathy for your situation, until I got to the part that said "I reaffirm that I am an important customer".
I don't doubt that you were mistreated to a certain degree, but really......
My wife and I have purchased many, many BMWs from our local dealer. All of these have been top-of-the-line models - M series, or equivalent (i.e. - the old 4.6is X5...). I would never, EVER, "inform" anyone of my "importance".
Your "importance", is to be determined by your dealer. If for whatever reason, they did not perceive your degree of importance to be sufficient enough to merit that special treatment which you desire, then perhaps the problem lies not just with the dealer... just a thought.
Conversely, is losing a great dealer REALLY worth not just sucking it up for $35? We might wax lyrical forever about the principle of it all, but at the end of the day, perhaps it would be better to simply go over this with the service manager, let it be known that you are not happy with it, and live to fight another day. There is obviously a reason, or reasons for you having purchased so many vehicles from this dealer. Would that not overshadow this recent event?
Just my two cents.
"Anima sana in corpore sano"