This antifreeze has to be mixed with water, 50:50, as specified on the bottle. The weird thing is that 50:50 mixture only has a ~ -18*C freeze point, which is not enough.
@John - you are right. As i said, in the Peugeot they put pre-diluted Peugeot antifreeze and measured it with the same tester and the result was: ~ -37*C (-34*F -ish).
I don't know how to get the BMW antifreeze to the same point. I will probably go to BMW and ask them to check the coolant freeze point and replace it, if necessary (although it had just been replaced at a local indy)
BMW 320 dA LCI, BMW PPK - 197HP, 2010, sapphire black, steptronic