Someone did the actual math (don’t have the link, sorry) and came up with a temperature-related variance of less than 0.5 PSI.
So - if the original rumor is based on 2lbs lighter than the 13.5 max psi - that means the balls were “under inflated to 12 lbs - not 10.
No one knows - ‘cause the NFL isn’t doing a damned thing to clear up what is rumor and what is not.
I took a shot at it in my post #60. Disclaimer: It was done before my usual two cups of morning coffee.