Allow calls on other devices
MacBook Pro with Retina display, OS X Yosemite (10.10.5)
If it doesnt actually cause any issues, I'd be inclined to ignore it.
Do you use an Airport base station by any chance.
I noticed the same thing on my iPhone 6. It shows my MacBook Pro twice, and my iPad once under the "Allow calls on" settings. It doesn't seem to cause any functionality issues but it would be nice to remove devices that either aren't used or don't exist.
I've tried Resetting Network Settings, and Signing out and then back in on my iPhone, Shutting off Cellular calls in face time on both MacBook and iPad, Turning off handoff on iPhone, but every time I go back into the Phone settings I see the device.
Allow calls on other devices