If the request is determined to be a substantial change, the planning and building director shall refer the request to the commission for noticed public hearing and recommendation prior to public hearing by the town council. If the substantial change is a change in density of land use regulation, the public notice shall be in the same manner as that for a rezoning, per STC § 18.91.060. If the substantial change is a change in policy regulation or design regulation, the public notice shall be in the same manner as that for a code amendment, per STC § 18.01.070.