Percent decrease not even close.

We have now changed the amount drawn per km from 168wh/km to 100wh/km but still the app says we would have 10% less left then what we actually do. We are now at 54% according to the app we should be at 43%. Would be great to be able to change the actual percent while driving in the cars infotainmentsystem instead of every time we stop change where we left from and how much battery we actually have left. Starting to think this app ain't worth keeping...