Power to issue instructions: Board-issued directions bind tax officers to secure uniformity in implementing the Act. The Board may issue orders, instructions or directions to central tax officers to secure uniformity in implementing the Act; such instructions are binding on those officers and others implementing the Act. Certain mentions of a Commissioner in specified provisions are construed to mean a Commissioner or Joint Secretary posted in the Board, who may exercise the referenced powers only with the approval of the Board. The provision reflects later insertions, substitutions and omissions amending cross-references.