I think for some the SM rules may actually define some of the details of what some of these ragged-edge, tech shed-legal IT motors are doing.

Think about the valve allowance. It's possible you are right on the money for the reasoning behind the allowance. So if the spec is set so that you don't have to go after 100 heads and find the perfect one, you could surmise that the spec is a 'perfect stock' unit.

Guess what? You got to do that in IT to be at 100%. Right? (All based on the accuracy of your assumption in the hypothetical).