(1) Any shelter and sanitary facilities which have been constructed and are presently being maintained in accordance with an agreement heretofore entered into between the parties in interest, shall be deemed a complete compliance with these rules and regulations, until such time as a specific complaint is filed with the Commission claiming that, on account of changes made in the uses of the facilities, such facilities are inadequate. Provided, nothing herein shall be construed to abrogate or limit any agreement between the interested parties now in effect which provides for better or more adequate facilities, or to prevent the negotiation of such an agreement in the future.