Any church, religious society, charitable corporation or nonprofit organization granted a tax exemption pursuant to this subchapter, shall pay to the county and other political subdivision in which the project is situate, in lieu of taxes, a special assessment in an amount not less than 10% of the gross rentals derived from the project, less the cost of utilities and the cost of providing special social services to the elderly persons residing in the project. This sum shall be divided between the county and other political subdivisions having authority to levy ad valorem taxes on land and improvements in which the project is situate in proportion to their respective tax rates.