At the regular or special meeting, when the completed application is reviewed, the Planning Board shall determine whether a public hearing is necessary. A public hearing must be held within 62 days after the completed application is submitted to the Planning Board and with 10 days' prior public notice in the official newspaper. In addition, the applicant shall give notice, in writing, by certified mail to all property owners of the land immediately adjacent to, extending 500 feet therefrom and directly opposite thereto, extending 500 feet from the street frontage of the land in said application. If in an agricultural district, such notice shall be given to all property owners within 500 feet of the lot boundary. The applicant shall mail these notices at least 10 days in advance of the hearing and furnish the Planning Board with post office receipts as proof of notification.