All scales tested and approved by the commissioner shall be located within this state or within an additional adjoining area extending at least five miles, but not more than ten miles, from the state boundaries; the outside boundary of such additional adjoining area beyond the five mile minimum to be fixed by the Commissioner of Weights and Measures and to be based upon the commissioner’s facilities for testing and inspecting scales located outside the state and for maintaining reasonable supervision of weighing at such scales. The commissioner shall charge a fee of ten dollars for testing and approving any scales located outside the state.