The Director shall advise the Owner/Applicant of the recommended reimbursement charge and area by letter sent by first class mail and by certified mail, return receipt requested. The letter shall enclose an original latecomer reimbursement agreement for signature by the Owner/Applicant, who shall return the executed agreement within twenty-one (21) calendar days after the date of the letter. If the Owner/Applicant fails to return the executed agreement within said period, the application for latecomer reimbursement shall be deemed null and void and terminated. Upon written request filed with the Director within seven (7) calendar days after the deadline, and upon proof of hardship and/or excusable neglect, the Director may set aside the application termination and grant a period of up to twenty-one (21) calendar days for return of the executed agreement. The decision of the Director shall be final.