My friend just bought his 3T and after a week he installed Accubattery App on my recommendation n his battery was shown as 2980mah (3400mah original) and still shows the same even after 3 weeks of installation n use ... how this can happen. I also installed and it reported same 2900mah n I'm using mine since January/FebAccuBattery app on Play Store. You have to charge and discharge the device a few times for it to show results.
Sent from my SM-G955F
Either the app has some issues measuring true battery capacities or it is buggy.
Sent from ONEPLUS 3T