The Hillside protection zone shall be an overlay zone of the zone classifications set out in Section 17.40.010 of this title. Any permitted use in a district overlaid by the Hillside protection zone is a conditional use. Conditional uses authorized in districts overlaid by the Hillside protection zone remain conditional uses. In case of conflict between the provisions of the existing zoning classification, building code, subdivision ordinance and/or other city ordinance and the Hillside protection overlay zone, the most restrictive provision shall apply. Nothing contained herein shall be construed to expand a use, make less restrictive a use, or allow a use which is not otherwise permitted in the zoning district overlaid by the Hillside protection zone.