I agree with this. The pressure listed on the tire is the maximum that the tire has been designed to withstand- not the optimal pressure (which is dictated by many variables).

As for your method of finding that 'optimal' pressure, I don't think the contact patch acts in as simple a fashion as you suggest. Under-inflation caves the contact patch, yes, but in all dimensions- the cave you see in a 2D cut-away is not accessible from the front or rear of the tire.

Have you performed this method?
I may just be confused by what you described.