Line extensions required pursuant to sections 90-239 or 90-240, above, shall be made and completed within reasonable periods of time consistent
with the relative cost and periods required for planning and construction. A franchisee
shall not be deemed to be in breach of said sections until after written notice is
mailed to the franchisee by the cable television commission identifying a particular
extension which the commission asserts is required. If within 30 calendar days following
mailing of such notice the franchisee has not filed with the clerk of the board of
directors of the commission a written notice specifying the date of completion of
such extension, the franchisee shall be deemed to be in breach, if it has failed to
comply with the requirements of said sections, from and after the expiration of the
30-day period. A franchisee's designation of a completion date shall not be presumed
to be reasonable or binding upon the commission.