OK, I messed that up, I should have written that the higher volume tire should have a wider contact patch, not larger. BRR's measured casing width of the GP 5K is also 2mm wider than than the S TR.

This all assumes that the tire construction is the same between the two models, as that also affects the contact patch shape. That seems highly unlikely, which is another reason why comparing two different tire models to try to prove that tubed tires are just as fast as tubeless is meaningless.