So far I had just looked in my books where I found a drawing of an almost identical car in von Fersen's book described as a 1912 Typ BT 6/16 PS. After a deeper search I found the same drawing in a 1912 Motorfahrer magazine described as a 5/12 PS and used in MAF ads without any type specification. So I conclude that we are both talking about the 1911/1912 version of the MAF and it may be that there were no differences in appearance between the different types. The point is yours.
