well that’s a pleasant surprise 
the advantage of the adjust feature I just add in my previous software package . it works nicely to recalibrate for various anomalies. ie: resistors and even crack faulty CTs.
I have one emontx sheild that has faulty or wrong size resistor on it from factory that I never got around to changing and it always registered 10% higher then all the other CT ports - was easily corrected using the adjust feature just lower it 10% less then what ever the other CTs were set at. and it maintained the same accuracy as the the other CTs.
so I thought i try it on a cracked CT that was registering 20% lower then a normal functioning CT - adjust it up 20% - and it maintained the same accuracy – 
Bonus
I think I will add the adjust feature to my normal emonlib since it so handy
here a sample: the first one is the cracked CT the second is the normal CT the third is the bad resistor on CT port- the last is the volts -my tester bounces between 884 and 891 on my resistant load also I am testing on a light extension cord so I get variable voltage drops. to see it it maintains the same accuracy under different loading conditions - which it does
893 882 892 118
882 884 890 119
887 883 882 119
883 884 880 118
886 882 886 118
883 885 891 118
888 886 885 119
885 888 883 118
897 884 885 118
893 887 894 118