That is true as far as it goes, but wagons were built to carry loads and loaded wagons were allowed to have their buffer height 3" below that of locos and brake vans. The point is that calls for a buffer height 'standard' to the nearest 0.1mm are inauthentic.
You're being disingenuous Bill... A standard is exactly that - a level that should be aimed for to eliminate ab-initio variation in design. The Railway Clearing House first specified a standard for buffer height in 1887.
Then can someone please tell me why if the RCH allowed a tolerance of 3" (that's 1mm in 4mm scale), people here think that the tolerance in 4mm scale should be a whole order of magnitude tighter, i.e. to the nearest 0.1mm?
Even the putative quoted standard height of 13.8mm is spurious, since the GWR specified a buffer height of 3' 5 1/2" for coaches and 5' 4 1/2" for locos.