Isnt that a bad idea for a phone? I mean you usually have 1, 2 or at least very few addresses on a phone in comparisson to the number you might have on a regular machine. But in order to send the change to a fresh address the phone would have to generate a new key pair and your backup would need an update. On the other hand if you allready have several private keys and addresses generated you could just add one of them as another receiving address.