At least 14 days and not more than 21 days prior to designating a new or expanded natural market area, the commission shall hold a public hearing in the proposed area to determine whether to designate that area as a market. As a basis for its determinations, the commission shall solicit and seek to receive oral and written testimony in addition to the data received through the implementation of the information gathering procedures of its rules and regulations. Due notice of the public hearing shall be given by publishing the notice as provided in the Maine Administrative Procedure Act, Title 5, chapter 375.   [PL 1979, c. 672, Pt. A, §39 (NEW).]