I have a question about insurance. I will be having my anatomy scan on Friday and I have Blue Cross…

I have a question about insurance. I will be having my anatomy scan on Friday and I have Blue Cross Blue Shield insurance the basic plan I asked the lady if it was covered and She said it showed the amount of $174. But a few weeks ago when I called the insurance they said anything that had to do with maternity was all covered. Why is it showing I have to pay $174? Ugh insurance plans are soo difficult to understand.