Is this common practice? (Medical Billing)

So I recently had hand surgery from a surgeon who was out of network, but who I chose anyway because he was highly recommended. I just got the bill. Included are 4 different activities (tendon repair, use of operating microscope etc. Total bill pre-insurance: $8000.00. Everything is reasonable so far.

Then there is a second page. for a “assistant surgeon”. Exact same four procedures listed for the exact same cost, an additional total of $8,000. Looking up the “assisting surgeon” online it turns out she is not an actual surgeon but just a PA (Physician’s assistant). I find it hard to believe that they could charge the same amount for a nurse assistant as they could for the surgeon himself. Is this standard accounting practices? a billing error? fraud?

For now I’m going to wait for my insurance company to hash it out with the surgery group, but any advice from knowledgeable dopers would be welcome. I also hate to imagine how many people without insurance would just go ahead and pay the whole thing.