§ 550. County assessment of real property. 1. If the alternative form of county government, or the modification or change of any such form, shall provide for the transfer to the county of the function of assessment of real property from the towns, villages or cities, the director of finance, or county treasurer, as the case may be, shall have all the powers and perform all the duties of the assessment officers of the unit of local government from which the functions of assessment have been transferred to the county. All provisions of law which apply to the assessment officers of such units of local government shall apply to such officer, except that the board of supervisors may, by local law, enact such provisions relating to the assessment of property in such units of local government as shall not be inconsistent with the general plan for the assessment of property contained in the tax law and subject to the general supervision and authority of the state tax commission, but which may include, without limitation of the power thus conferred, a rearrangement of dates for the performance of acts, or the method of giving notices, or the place of filing the assessment-roll so as to coordinate the assessment work; provided, however, that the county board of assessment review of such county, if there be one, shall review such assessments in the manner provided in this article. It shall be the duty of the director of finance to adopt scientific methods of assessment, including tax and land value maps in the form approved by the state tax commission.

2. If the function of assessment of real property is transferred from the towns or the cities to the county, the school districts or parts thereof within such towns or cities shall use the county assessment.

3. If the alternative form of county government provides for the transfer to the county of the function of assessment of real property from any units of government within the county, such form may provide for a board of assessors, either three or five in number as provided in the petition or resolution by which the form or the question of adopting such board is initiated to be appointed by the board of supervisors upon recommendation of the county executive. At least one of such assessors shall be a resident of a city in the county if there be any such city, and at least one shall be a resident of the county outside of any city. In case of the appointment of a board of assessors, the director of finance shall have general supervisory power only over such board, and shall not have charge of the administration of the function of assessment of real property for taxation, which function shall be performed solely by the board of assessors.