Uh, not completely sure but "controlled flexing of the carcass" would build a set amount of heat related to speed and tire pressure and the asphalt trying to rip the tread off the carcass would add more heat related to acceleration forces and the size of the contact patch plus another hugely variable amount for the amount of sliding friction. If Michelin technicians were in attendance of the Metzeler into then I would understand your skepticism but it'd be a safe guess that whomever was there knows more than you and I ever will and likely dropped the tire pressure to increase the size of the contact patch and increase grip.