18.—(1) Where in accordance with section 16(10) of the Act (determination of questions arising under that section) a person has referred a question to the Secretary of State for his determination, that application shall be accompanied by a fee calculated in accordance with paragraph 1 or 2 of Schedule 4.
(2) Where in accordance with section 50(2) of the Act (determination of questions arising between approved inspector and developer) the person proposing to carry out the work has referred a question to the Secretary of State for his determination, his application shall be accompanied by a fee calculated in accordance with paragraph 3 of Schedule 4.