The Department may not change the administrative classification of a nonconforming official testing station from its present classification to a less favorable classification upon a change in ownership of the station, if (1) the nonconforming official testing station has held its present administrative classification since July 1, 1972, and (2) the station meets all requirements for its present classification, other than the requirement of having an exit door in direct line with the safety test equipment and (3) the station is located in a county with no other class “A” or class “C” official testing station.