I too am not understanding totally. When a provider/group contracts with insurance, they indicate what type of provider they are, in the contracting process. Urgent Care has a specific taxonomy code in regards to this. Is your client an urgent care facility provider/group, or not? If so, they should be contracted as such.
I have never heard of attaching a statute to a claim, payment is determined by what the POS is on the claim. If they are Urgent Care, that is one POS. If they aren't, that is another.