When I asked about "what tolerances do they allow", I was referring to the "accreditation" people.
My suspicion is that modern patient weighing scales may be more accurate than the techniques employed by the "accreditation" labs.
In my opinion, nonsense such as this should be challenged whenever and wherever it appears. I believe it to be yet another scam based upon very little clinical need (or possibly none at all).
Newtonian physics should suffice!
Meanwhile, what about precision balances such as those found in clinical laboratories and pharmacies ... do the "accreditation" gang poke their noses in there as well? Or do they limit their interests to "low hanging fruit"?