Not seeing the same concerns as to number of units in circulation or fact they are separated from each other. Point of the exercise is to determine if each is seeing variations in testing the same exact sample of their water as Parker detailed in the video I posted. Goal is to identify how accurately the results match each other when the variable hasn't changed. Variable being their sample water or reference solution.
If GHL was aware of this problem then why did they send the units out? Perhaps they aren't aware because it doesn't occur with every unit. Perhaps going forward then each unit should be tested to confirm this isn't a concern.
You said "exact same sample of water". How is that going to be done? Maybe I'm being direct with the use of "same example" though.
My comment about GHL being aware is a direct relationship to general availability or lack thereof. It isn't available for a reason.