Here's my advice for dealing with Trump. Pay very little attention to what he says, just watch what he does. He is a long term schmoozer and he tells people what he thinks they want to hear right up until he drops a hammer on them.
I said the exact same thing in almost the same words a couple of days ago. Right now Trump is focused on transition and he does not want to say anything that may disrupt that.
He knows that Obama is emotionally attached to Obamacare, so he is telling him that he is going to keep it, just to keep Obama calm for the next couple of months. If he said now that he was going to throw the whole thing out and start over, Obama may shut down, stop cooperating, and disrupt the transition. And there is certainly no reason to get Hillary's supporters even more riled up than they already are.
I agree with all you said. He says what he has to say to get the immediate job done as smoothly as possible. And that is what he is doing. You are spot on. We will not know how he really feels about anything until Jan 20.