Why would it need to change your behaviour - if your paying for something surely you have a right to have the bill explained to you and for you to be able to challenge individual items?
[NB I'm from the UK so I have no idea how medical billing works. But I do have plenty experience with lawyers and I know that getting a details breakdown of work charged is a really good idea.]
Well, at the point that you have a bill, you are kinda beholden to the people that sent it. You can't easily dispute a charge with our system. It would definitely be useful to understand the bill later on, if you could actually do something about it. My point is not being able to know the estimated charge before you choose a provider makes it impossible for the market to work, because competition can't happen, at least not with costs.
[NB I'm from the UK so I have no idea how medical billing works. But I do have plenty experience with lawyers and I know that getting a details breakdown of work charged is a really good idea.]