Interesting links, but are you really surprised? I could recite a lengthy story where the same size tyre from different manufacturers could make a difference of places in a race of several tens out of 50 odd competitors. Side wall flex, type of rubber, pressures are only some of the factors.
If it were simple then there would not be millions spent on tyre technology.
Once upon a time, not long ago it was considered that cornering or braking forces in excess of 1g were impossible. Now even non-aero cars are way above that.