(5) All officers and persons employed in the execution of this Act, other than Valuers, shall observe and follow the orders, instructions and directions of the Board: 1[ Provided that no such orders, instructions or directions shall be given by the Board so as to interfere with the discretion of the Appellate Controller of Estate Duty in the exercise of his appellate functions.] PART IMPOSITION OF ESTATE DUTY PART II IMPOSITION OF ESTATE DUTY Extent of charge