So the same ball with the same air pressure would weigh different in Denver than it does in New Orleans. That’s why there is a weight variance given etc. The weight variance is not a 1 to 1 with the air pressure.
I don’t think we are in disagreement. It has been pointed out that the pressure in the balls does vary due to temperature changes. Perhaps the league has check the balls once they are back at the typical inflation pressure to verify the pressure.
For instance, suppose the ball is at 15 psi at 70 F. But it is 40 F outside. If the ref measures the pressure at this time, he is going to get a low pressure. But if he takes the balls after the game and lets them warm up to 70 F, and then measure the pressure, the ball better be very close to 15 psi. Otherwise the ball has a leak or has been tampered with.
Likewise, you can wait for the balls to dry to measure the dry weight.