Final approval of a major subdivision shall expire 95 days from the date of signing of the plat unless within such a period the plat shall have been duly filed by the developer with the County Recording Officer. The approving authority may for good cause shown extend the period for recording for an additional period not to exceed 190 days from the date of the signing of the plat. No subdivision plat shall be accepted for filing by the County Recording Officer until it has been approved by the approving authority as indicated on the instrument by the signature of the chairman and secretary of the approving authority, or the vice chairman or assistant secretary in their absence, respectively, or a certificate has been issued as to the failure of the approving authority to act within the required time. The signatures of the chairman and secretary shall not be affixed until the developer has posted the required guaranties. If the County Recording Officer records any plat without such approval, such recording shall be deemed null and void, and, upon request of the municipality, the plat shall be expunged from the official records. It shall be the duty of the County Recording Officer to notify the Planning Board, in writing, within seven days of the filing of any plat, identifying such instrument by its title, date of filing and official number.