If you had fine battery reading, you'd better stay with original themes.
This mod is simply matching
99 with 90
98 with 80
...
91 with 10
90 with 0
As I've exactly the same problem as kingdixon.
Or you can check the battery level for full drain, then use notepad++ to open wps and change the battery part
Ah, I see what you're saying now...makes sense. I've not fully tested to see if it reaches 0 at 90%, but I'm on 91% at the moment so we shall see.