The Planning Board may extend the 190-day period for filing a minor subdivision plat or deed pursuant to paragraph a if the developer proves to the reasonable satisfaction of the Planning Board: (a) that the developer was barred or prevented, directly or indirectly, from filing because of delays in obtaining legally required approvals from other governmental or quasigovernmental entities, and, (b) that the developer applied promptly for and diligently pursued the required approvals. The length of the extension shall be equal to the period or delay caused by the wait for the required approvals, as determined by the Planning Board. The developer may apply for the extension either before or after what would otherwise be the expiration date.