It is my understanding that they sometimes have to do a full update when programming. In other words they reload all the software in the system to get you up to the latest software revs for all modules. This takes time. Apparently lots of it.
2011 328i Convertible
: Mineral White; Oyster/Black Dakota Leather; Premium, Sport, Value; Sport Wheel w/paddles; Heated Front Seats; Satellite radio; HK Sound
2012 528i Sedan
: Titanium Silver; Oyster/Black Dakota Leather; Anthracite Wood; Comfort Access; Side & Top View Cameras; Cold Weather, Premium; Technology;
: Titanium Silver; Gray Leather; Premium, Sport; Fold Down Rear Seats; Xenon Headlights; Navigation System; HK Sound
2001 X5, 2009 528i