When you do that then the Nexus 4 still appears in your list of devices on the play store right? You have to do something else if you want google to stop associating the device to your account I think but don't know what.
I think there was something mentioned on this forum, about deleting the data of google services or something similar before you wipe out the phone. Can't remember what it was precisely but I'm pretty sure it was mentioned here somewhere.
