Belton Park Resort

Hi Sir I have a question in calculating the incremental cost for the hotel. Incremental means extra and so if the payments are fixed then there is no extra cost or saving. Security costs: If the hotel and water park close, no changes will be made to the current arrangements for security whilst the premises are empty. Why the security cost is zero? when the hotel or park is close the security cost is zero. but if the keep open, the security cost will be charged.