I think the thing to understand here is that the non dealer route is illegal. The codes are supplied by third parties that make profit at BMW's expense. FSC license codes and MAP data are copyright. Taking the map data for free could well be theft, I've no idea if the map data is available FOC as I've only ever seen it charged for. Getting an FSC code is theft if not from a dealer (at least currently) as this is the license that is paid for to use the map data and BMW take a cut of this before passing the rest onto the mapping company. When you get the code from elsewhere, BMW make no money (hence theft) but instead pay the license fee to the mapping company, a cost only transaction.
Just sayin ...