I have had 5 BM's and have only ever used 98 but have noticed different petrol stations charge different prices above the advertised unleaded on the board.
Here in Melbourne, Shell now charge 18cents above the board price. Obviously a trick to claw back and force you to use a fuel voucher. BP I think is 14cents and not sure about Caltex, I need to double check.
M Sports Pack, Sapphire Black, Procede Rev 3, Alpina T3 trans flash, Gloss Black GTC wheels with Michelin 19" PSS, Gloss Black BMW Performance Grill