Powers of officers: state tax officers may exercise, delegate and discharge duties subject to the commissioner's conditions and limits. State tax officers may exercise and discharge functions conferred by the Act subject to conditions and limitations imposed by the Commissioner; officers may perform the powers and duties of subordinate officers; the Commissioner may delegate powers to subordinate officers subject to specified conditions and limitations; an Appellate Authority is precluded from exercising the powers or discharging the duties of any other State tax officer.