I just give reference from a user manual, no research from my part

so I guess/interpret the process should be like this...

- let's say with cold tires (parked overnight), you check the tires and you
want it at ie. 40psi.. you check your gauge and pump in air until you get
40psi

- let's say with hot tires (after a long run on highway), for some reasons
you check the tires and you want it at ie. 40psi.. you check your gauge and
pump in air until you get 43psi

which mean when the tires cool down you will have 40psi...

again my guess when hot, tires rubber expand and require 3 more psi...