Each supplier which becomes a party to an agreement under the provisions of section 70-1002 shall file with the secretary of the board a suitable map or maps, in such form as the board shall prescribe, showing either the service area or customers to be served. Whenever any changes occur in the service area, new maps shall be filed. Each supplier in the state which fails to file a map or maps showing its service area or customers to be served as established by agreement shall file a statement with the secretary showing the service area and customers actually served by it, what it claims to be its service area, stating the reason it has not entered into agreements with suppliers in adjoining service areas, and if a dispute exists as to furnishing service to any service area, the nature and extent thereof. This section shall not apply to agreements referred to in subsection (2) of section 70-1002.