Upon the filing of such recommendation by the Director of the Department of Public Safety, an annual allowance shall be awarded to such policemen or firemen who are permanently disabled as aforesaid in the performance of their duties, which said annual allowance shall be the difference between the amounts such person was paid when employed in the municipal service and any pension paid and any award under Workmen's Compensation, Title 11, of the Revised Statutes, and shall be paid during such disability in weekly installments in the manner as all salaries of the police and firemen are paid. After the day of final payment under any award under Workmen's Compensation, Title 11, of the Revised Statutes, the annual award shall be the difference between the amount paid such person when employed in the municipal service and the amount of any pension paid as aforesaid to such policemen or firemen.