BMW Coolant may already have surfactants, but probably not. The surfactant does not last very long, so even if it did, the efficacy would diminish pretty quickly, so I doubt BMW (Pentosin, currenly) would incurr the additional cost in production for a benefit that would not last the life of the coolant. They would not want to have to tell customers that they need to "recharge" the surfactant annually. All just to increase cooling ability that 99% of the vehicles it is used in do not need. In the case of Amsoil's coolant boost in 50/50 antifreeze/water, a new dose needs to be added annually or at 30k miles in order to maintain the benefits.For all we know the BMW coolant already includes surfactant.
Amsoil's test doesn't take into account that the thermostat and ambient conditions, and these could skew their results.
I can see a benefit to race cars that aren't permitted to use coolant products like the stuff we run in our cars and K-bikes.
As for the testing, the thermostat is a non factor as it would be open at all temperatures during the test sequence. Ambient temperature was kept the same for all test sequences as well, so that is a non variable.
Another big benefit of coolant boost in cars and trucks that us northerners like is a much faster warm up. Warm up times are reduced on average by 54%. Of course, you need to be a "doityourselfer" as you do need to "recharge" the coolant boost annually.