4. (1) Subject to the rules and orders of the Government regulating the terms and conditions of service of persons in public services and posts, appointment of income-tax authorities shall be made in accordance with the provisions of this Ordinance. (2) The Board may appoint ¹[²[Chief Commissioner of Taxes, Director General], Central Intelligence Cell,]³[ * * *] as many ⁴[ Directors-General of Inspection], ⁵[ Commissioners (Appeals),] Commissioners, Joint Commissioners of Taxes, Deputy Commissioners of Taxes, Tax Recovery Officers and Assistant Commissioners of Taxes and such other executive or ministerial officers and staff as it may think fit. ⁶[(2A) Notwithstanding anything contained in this Ordinance, the Board may, with the approval of the Government, appoint one or more person having appropriate professional skill and experience to perform such function as may be specified by an order issued in this behalf, and the person or persons so appointed shall be deemed to be an income-tax authority for the purposes of this Ordinance.] (3) Subject to such orders or instructions as the Board may, from time to time, issue in this behalf, any other income-tax authority may appoint any income-tax authority subordinate thereto and such other executive or ministerial officers and staff as may be necessary for assistance in the execution of its functions.