In the event the reduction in the number of parking spaces caused by the conversion of an attached garage to living space causes a dwelling unit to have less than the number of parking spaces required by Article XX, § 280-103B(1), the setbacks and requirements of Article XX, § 280-105F, above, shall not apply to single-family dwelling units preexisting at the date of enactment of this subsection that are located in the AC, R-1, R-1A, R-2, R-3, R-4, R-5, R-6, and GH-N Districts. The number and location of parking spaces permitted in the front yard under this section shall be subject to approval by the Township Engineer.