I don't know about that. But what I know is phone and apple watch will both receive a phone call. You can answer from either your watch or from your phone. Both will ring. However, there is a chance that if you answer your call from your phone, your watch will also "connect" even though it should not. I had a ghost call on my watch a few weeks ago and it last 35 min long after I hang up the same call from my phone.