I do not have SM-PCE002, so I can not use etube and I use STUNLOCKER, which reads the same BMS register. After 5 months, 10cycles and 800km my second battery shows health of 90%, so I will be using it as my main battery and waiting if it reaches 80% health during the 2 year warranty period.
I keep the battery data and GPS tracklog of my rides and I can do comparisons but I am not using it to calculate battery health just to confirm that decreasing health causes decreasing mileage and altitude. I explained this to another forum member that was questioning the mileage decrease with the health decrease.