That's only part of the function. The car will remember the last position the seat was in for that particular key - it doesn't return it to the preset for that key, it returns to the last position the seat was in for that key. If your last position was messed up, you can hit the memory button and return to the preset. This is how it was described to me and how mine works. Only problem is that sometimes when switching between wife's last position and mine, it cycles the seat all the way forward before going to my position. Works something like a garlic press if you forget to wait a moment before you get into the car.
2013 335xi MSport Alpine White/Coral Red, ZMM/337/Walnut, ZPP, 2PE, ZDH, 2TB, ZTP, ZDA, ZDB, ZCW, HK, Shades
2013 X3 35i MSport Black Saphire Metallic/Chestnut, black grill, everything but lane departure, BMW trailer hitch