Jon has been asked before if he used a choreographer and he found it quite amusing that anyone would think he did. It's all Jon. I would imagine that one reason he wouldn't be full-on while performing with another artist is to not disrespect that artist or seem like he's upstaging his guest. TV shows typically have smaller stages and they have to work with the camera crew. It's not the same setting as a stadium or arena show.

Becky