(i)Detention in military custody beyond two months of a person subject to the Act, who is not on active service and in whose case a Court-Martial for a trial has not been ordered to assemble, shall require the sanction of the Chief of the Army Staff, or any officer authorised by him in this behalf with the approval of the Central Government, who may sanction further detention for a specified period, which he may extend from time to time, subject to a total period of detention of three months.