I'm not sure, which app should do that. Only batt related app I have is actually battery graph - i will try to find out, whether this one could be causing it.
Yes, I'm using 1.3 and so far i can't really tell the script accuracy/reliability - so far i was able to notice, that there is about +-4% difference between the calculated percentage from your script and the "native" meter.
I'm successfully using the script only since today ... so i can't really provide much more value at this point..
-M.