I have some comments on points raise a few posts ago.
My basic proposal is that better measurements can be made by monitoring tire pressure to keep it the same or slightly above that use in calibration, so that the caibration constant is more nearly constant. I am not proposing to calculate the calibration constant from pressure measurements.
Post-calibration is unnecessary in the method, but Paul's suggestion to retain it might be a good interim measure to provide method validation. Also it could be used as a check that a measurer was making correct pressure measurements.