A brokerage agreement that includes a provision that grants a dealer the exclusive right to assist, solicit or negotiate the sale or exchange of an interest in a manufactured home, mobile home, manufactured building or commercial coach or factory-built housing on behalf of a client is enforceable if the agreement:
1. Is in writing;
2. Sets forth the date the brokerage agreement expires;
3. Does not require the client to perform any act concerning the brokerage agreement after the agreement expires; and
4. Is signed by the client or the client’s representative and the dealer or the dealer’s representative.