It really has nothing to do with the app you choose. It has everything to do with Motorola and how they handle the battery increments on their device.
There are a couple apps like Battery Left, which try and predict how much actually physical time you have left, and equate that to their own little percentage which sometimes is very far off what the phone says it is. At least it was when I used it on my OG Droid, over a year ago.
Honestly, battery life is an approximation. Having 1% or 5% increments is really just an illusion of more accuracy. There is no more accuracy than with 10% increments. Your only options are to get an app like I mentioned which basically does its own approximation, completely separate from the phone's. Or you can get a different device, heh.
Chances are if you stop stressing about it, you'll soon forget about it.