In fact, the nominal value of 9999 silver with approx. 62 MS/m is slightly higher than that of 999 silver with 60.5 MS/m. Of course, when measured in practice, the values deviate slightly from the nominal value due to temperature, minting and packaging.
Coins with the fineness 9999 can therefore be in the higher green and sometimes also in the yellow zone.
Silver coins with "only" 999 of 1000 parts of silver are now and then in the lower green or even in the zone of copper (displayed on the GoldScreenSensor).