Several small factory of digital power meter in China, they try to advertise their "High End" model, about compliance to western power efficiency standards.
And they use the description: power meter with 6 Level power efficiency.
For unknown reason, the Chinese marketing selected the American description of power efficiency standards.
And they refer to DoE Level VI regulation within the USA.
Translations:
DoE (Department of Energy)
Level VI (Roman number of 6)
This standard went in to effect in the US February 10 2016
In the world of digital power meter, the above standard, this translates that the meter or power tester, this is able to measure reliably down 0.5 Watt (500 mW).
At the year 2024, the European COC Tier 2 this is more strict, the compatible instrumentation it must be able to measure reliably down to 0.075 Watt ( 75 mW) for PSU at the range of 1 Watt up to 49 Watt (power delivery).
In conclusion, the product designers in China, they need to update their digital power meter product design again, so this to be modernized enough, for a true compatibility with the latest standard.
Personally I do believe that COC Tier 2 this will never be updated again regarding minimum required measuring levels.