Section 17.08.070 notwithstanding, a rear yard may have a depth of not less than ten feet if that portion of the rear yard less than twenty (20) feet in depth is compensated by open area within the same or adjacent yards on the same building site that exceed side and rear yard requirements by an area at least equal to extent of building coverage of the twenty (20) foot, rear yard. Said compensating area shall be considered a required yard in accordance with Section 17.52.330. (Prior gen. code § 8-26.6.1)