Section 6(1)(ii) in The Customs, Central Excise Duties and Service Tax Drawback Rules, 1995
(ii)the Assistant Commissioner of Customs or Deputy Commissioner of Customs, as the case may be, may extend the aforesaid period of three months by a period of three months and the Principal Commissioner of Customs or Commissioner of Customs, as the case may be, may further extend the period by a period of six months;