I've heard/read that indicated battery % fluctuates when using this battery,especially when you get down to 15% or below,possibly :questionmark: due to the nature of the construction of the battery,essentially three separate batteries wired/connected together.
After about six weeks of using this battery,I've found that leaving the charger on the phone for at least a couple of hours after the phone says that it's charged gets the best result,waiting until you see both the icon appear in the left corner of the notification bar showing a full charge & the message on the lockscreen that says "charged".
FWIW,I'd uninstall any 3rd party indicating apps (GSAM/BBS,etc..) & to a lesser degree,not worry about the stock battery usage app & get back to what the whole smartphone experience is supposed to be:Enjoying your phone.