Just last week or two I saw one of those ‘How do they do it’ type cable shows and they had the NFL football factory spotlighted. They are initially inflated at the factory to the correct PSI at the room temp of the factory inspection room just before they are put in the shipping container to go to the games....................
A team could just ice the ball down to deflate, too. Or stick by one of those heaters to over inflate it for kicking. I don’t think there any rules about all of this?