When an application for a conditional use has been filed with the Board of Supervisors, and the subject matter of such application would ultimately constitute either a subdivision or land development as defined by this chapter, no change or amendment to the zoning, subdivision and land development, or other governing ordinance or plans shall affect the decision on such application adversely to the applicant, and the applicant shall be entitled to a decision in accordance with the provisions of the governing ordinances or plans as they stood at the time the application was duly filed. Provided further, should such an application be approved by the Board of Supervisors, the applicant shall be entitled to proceed with the submission of either land development or subdivision plans within a period of six months or longer as may be approved by the Board of Supervisors following the date of such approval in accordance with the provisions of the governing ordinances or plans as they stood at the time the application was duly filed before the Board of Supervisors. If either a subdivision or land development plan is so filed within said period, such plan shall be subject to the provisions of the Municipalities Planning Code, as amended.