Would it be correct to think that 5 degrees of temp change or 20% humidity change could make a .05 difference? It just seems hard to attribute to the oil alone, unless all the parameters were tightly controlled.
Mobil 1 is a pretty thin oil across all temps, and unless the oil temp was over 200 degrees, it would actually still be thinner viscosity than a standard dino oil of the same hot temp weight. Might be being pushed/blown off of the rings easier.