The best way to get ultimate bill predictability is with Volt.
Go to your mobile app > account tab > set up your Volt. Set your contribution to 20% more than your average bill (not sure what that is? Just think about last weeks bill).
Set your trigger to the same amount.
This should mean your regular payment to Flick each week is the same, if your bill goes over that amount (your trigger) then your Volt should cover you. Yes to predictability!