I haven't yet figure out that Chigurh worked for anybody - but I'll have to watch it again. It's a bit confusing.
What I Do want to know (I must have missed something) is how did Chigurh find the hotel he was staying at in the end where he was waiting for his wife? He kills the bounty hunter, answers the phone and talks to him and then changes his plans where his wife should go.
How did he find him there? since he no longer had the transponder.