If after considering the matter at a public meeting as provided in RCW 36.70.620 the board deems a change in the recommendations of the planning agency to be necessary, the change shall not be incorporated in the recommended control until the board shall conduct its own public hearing, giving notice thereof as provided in RCW 36.70.590, and it shall adopt its own findings of fact and statement setting forth the factors considered at the hearing and its own analysis of findings considered by it to be controlling.