Thus the Troemner student use weight set I purchased from eBay for about half the price the larger range RCBS & Lyman calibration weight sets are actually literally made to a higher standard.
The preowned vintage apothecary set I purchased from eBay - I honestly dunno but given that medication doses have been commonly specified in milligrams (in one system) for quite some time now, perhaps Class 2?
In the world of my career field, in the subspecialties of industrial control systems, structured hazard evaluation, and risk mitigation, there are specific numerical values to things such as 1 out of 1 (1oo1), 2 out of 2 (2oo2), 2 out of three (2oo3), middle of 3, average of 3, and so on input signals vs courses of action that has its own realm in addition to instrument signal quality and calibration standards. Similar, but far more detailed, and takes the calibration standards used, the calibration frequency of the watches, the build quality and factory QA/QC used for the watches into account along with the number of watches. We've outgrown the two watches aphorism for quite some time now, at a price point, and such logic is in use 24/7/365 for processes with higher potential risk ranking than individual cartridge reloading in terms of both direct human health and environmental impacts.
And yet incidents still occur.
ETA - it's all good discussion.
@LiveLife is undoubtedly a deeper expert specifically WRT scales than myself without a doubt. Also undoubtedly with auditing.
My work at the sharp end of the stick was in up front design often with respect to systems never explored before, looking ahead towards audit requirements, and incident investigation for causal factors and figuring out mitigation in a structured quantitative environment, something that was in its infancy when I began my career - the famous Union Carbide incident in Bhopal, India as well as the shipwreck of the Exxon Valdez occurred as I began my career and was still a university student for examples of how things used to be.
