Section 6(1)(iv) in The Customs and Central Excise Duties Drawback Rules, 2017
(iv)an application fee equivalent to 1% of the FOB value of exports or one thousand rupees whichever is less, shall be payable for applying for grant of extension to the Assistant Commissioner of Customs or Deputy Commissioner of Customs, as the case may be and an application fee of 2% of the FOB value or two thousand rupees whichever is less, shall be payable for applying for grant of extension to the Principal Commissioner of Customs or Commissioner of Customs, as the case may be.