You are quite likely right, and this is a valid if legalistic defense. If the Patriots inflated the balls to the minimum allowable pressure in a warm room and then took them outside early enough to cool off before the game, the balls would end up about 2 psi below the designated pressure. The under-inflation could be both intentional and arguably not quite a violation of the rules.
Going forward, the refs should inspect every ball they can put their hands on. As for the past, the refs (potentially) blew yet another call, but the teams are not going to go back for sloppy seconds. The Patriots got what they wanted with their undersized balls.
They inspect every ball that will be used in the game. The balls are controlled by the refs until 10 minutes before the game. They are then turned over to the ball boys.
warm room and then took them outside early enough to cool off before the game, the balls would end up about 2 psi below the designated pressure.—
We can run the numbers:
P1 x V1 / T1 = P2 x V2 / T2
T is absolute temp
if 75 f inside
if 45 f outside
use P1 minimum of 12.5
Assume V is constant (probably not quite)
12.5 / (75+460) = P2 / (45+460)
P2 = 11.8
Looks like >2 psi means tampering
The balls were about 15% defeated. 2 psi low for 13 psi ball. Because temp and pressure are proportional, that would equate to a 40 degree celsius drop in temperature or 72 degrees F. The T in the ideal gas law is based off of the Kelvin scale.