As far as I can see the notification is only cosmetic.
If you are not making calls, it will not incur charges.
This app only works when you make a call and I think that it is perfectly fine to disable the notification. See my other post about how to close the app without having to force close or use the home button.
I will monitor battery drain and call charges; if there is anything untoward I will post an update, and also log a complaint with BT!
Edited by killerheels (Fri 29-Mar-13 21:05:56)