@grrlscientist
In theory, it should not be a problem. The insurer simply provides services the payor contracts for. But in the upside-down world of US medicine, the people contracting for the coverage, the people paying for the insurance, the people ordering the procedure, the people performing the procedure, the people billing for the procedure, the people receiving the procedure, and the people approving the claims are all different people.
@grrlscientist
And it benefits the insurer to pay more slowly, as they are investing that money. So they make it hard to know what diagnoses are accepted, requiring billers to re-code and resubmit bills without any guidance. It can be very illogical - like, they may require a very specific diagnosis for the office visit, but only pay for the non-specific code for the lab ordered during that visit.