After September 20, 1985, it shall be unlawful for any mortgage trust deed or land sale contract to maintain a clause or statement which prohibits the owner from applying for the benefits of the deferral of special assessment for local improvement as provided in ORS 311.702 (Definitions for ORS 311) to 311.735 (Rules). Any such clause or statement in a mortgage trust deed or land sale contract executed after September 20, 1985, shall be void. [1985 c.167 §11]