Doctors: when you tell a patient their insurance covers a procedure, do you mean 100%?

I can’t tell you how many times I have received a surprise bill from my doctors. So, I started asking if my insurance covers something before allowing a procedure, and I still get surprise bills. I feel like I must be miscommunicating, probably partly my fault, with my doctors.

Like, when I had an MRI I had to pay around $200 at the time of the scan, they told me that was my total responsibility, and then I get a bill for the doctor who reads the scan. In my mind I am thinking how much do I owe for my MRI and obviously reading it, what is the point if it is not read?

A few months ago I went to an ENT, and paid $330 out of pocket, at the time of the appointment I asked how much would be my responsibility and charged it to my credit card, and still got a bill for another $100+ a month later. When I called they said it should be just $26 something. Their explanation is it is because of my insurance, but doesn’t the doctor have a responsibility to quote me the correct amount?

If I ask a doctor, “does my insurance cover it?” I mean I will not have to pay anything out of my pocket, do doctors mean the same thing when they answer me, “yes, your insurance covers it.”