(b) The commissioner shall increase or decrease the residential assessment ratio to account for a change in level of assessment in the total assessed value of residential real property or, if not available, of all taxable real property. For purposes of this section, "change in level of assessment" has the meaning set forth in section twelve hundred twenty of this chapter except that a change in level of assessment shall be determined with reference only to residential real property if the necessary information is available.
(c) The residential assessment ratio shall be made available at the office of the county director of real property tax services, the office of the county clerk and the office of the assessor or, in a city with a population of one million or more, the office of the tax commissioner of such city. Such ratio shall be provided to the office of court administration for distribution to small claims hearing officers. 2. For purposes of this section, assessing units participating in a coordinated assessing program pursuant to section five hundred seventy-nine of this chapter shall be considered to be a single assessing unit.