Producers or stewardship organizations acting on behalf of producers that prepare, submit, and implement a paint stewardship program plan pursuant to RCW 70A.515.040 and thereby are subject to regulation by the department are granted immunity from state laws relating to antitrust, restraint of trade, unfair trade practices, and other regulation of trade and commerce, for the limited purpose of planning, reporting, and operating a paint stewardship program and proposing and establishing the architectural paint stewardship assessment required in RCW 70A.515.040(1) (c) and (d).