Two exceptions to this compensable interest prohibition exist:

(a) The prohibition will not apply to real property improvements lawfully constructed by a concessioner with the written approval of the Director in accordance with the express terms of a 1965 Act concession contract; and

(b) The prohibition will not apply to real property improvements constructed and owned in fee simple by a concessioner or owned in fee simple by a concessioner's predecessor before the land on which they were constructed was included within the boundaries of the applicable park area.