When it deems it to be for the public interest, the board may initiate consideration of an ordinance establishing an official control, or amendments to an existing official control, including those specified in RCW 36.70.560. The board shall first refer the proposed official control or amendment to the planning agency for report which shall, thereafter, be considered and processed in the same manner as that set forth in RCW 36.70.630 regarding a change in the recommendation of the planning agency.