A few years back one of the UK locos ran an exercise to check the accuracy of their weights. Aircraft were weighed in the hangar during maintenance to verify actual weight against the recorded figures and also selected at random as they entered the apron after a flight and directed onto a stand equipped with pressure pads. They were marshalled carefully onto the three pads and after about a minute, if even that, were able to disembark pax normally. Results were correlated with the flight papaerwork and processed.
Results showd the standard weights used were remarkably good, iirc something like a 2-300Kg deviation from the paper figure which on a 60t aeroplane is extremely accurate.