Unless a maximum height regulation is stated in § 27-305, Use Regulations, for a specific use, no principal building or structure shall exceed 35 feet and 2 1/2 stories in height. For any building or structure accessory to a dwelling, which building or structure is located at the setback line applicable in the underlying zoning district, shall be limited to a height of 14 feet; however, the height of the building or structure may be increased by one foot for every two additional feet the said building or structure is located away from the setback line to a maximum height of 25 feet. For exceptions, refer to Uses, §§ 27-305, Subsection 1, Use A1(3), 27-305, Subsection 9, Use I6(2)(c) and 27-305, Use I8(9).