The bank will finance based on the financial performance, which should materially be based on the revenue from lot rent minus expenses. If the Seller is making a killing on the utilities that’s a red flag. In a lot of states flat fee submetering is not allowed - should be RUBS or meter readings.
While a quick Google search did not return anything on Arkansas submetering laws, you should consult with an attorney after you get the park under contract. Some states don’t have submetering laws, but they do have laws against outrageous fees for services - which this could apply as a means to regulate it.