When people post examples, they often use simple and easy to understand numbers. In actual practice, this one often does turn out to be more expensive than $30. If you wanted to think of the example on a percentage basis, you could say that the in network doctor's bill was paid in full, but discounted. Whereas the out network doctor's bill was paid at 70%.
My particular health plan will pay out of network doctors, etc., at a maximum of 115% of the network rate or Medicare rate (I don't exactly remember which at this point) in an EMERGENCY situation. I suspect that my premium for my plan is a little higher than yours because of this feature. There are tradeoffs will most insurance and this is one of them.
For an elective surgical procedure (not an emergency), I would definitely find out in advance who the consulting physicians, labs, etc., are going to be and verify that they are within network. Obviously, you may not be able to protect yourself totally, if something unexpected happened. But, you probably can find out what is reasonable and customary with whatever procedure is being scheduled and go from there.