Shell’s previously-denied protest or its already-pending court action constituted a "drawback claim filed within six months after” the enactment of the 1999 amendments. (Emphases added.) 23 . Shell’s argument that it would have been futile to file a drawback claim for HMT and ET in the six-month grace period has no legs, as discussed in section III.B.l below. See generally Aectra, 565 F.3d at 1373-74. 24 . Cf. Aectra, 565 F.3d at 1370 (as to 2004 amendments, acknowledging Congress’ authority to "limit the right [to claim drawback for HMT] to those who had previously attempted to claim it within the three-year limitations period”). 25 . See also Aectra, 565 F.3d at 1373-74 (citing United States v. Clintwood Elkhom Mining Co., 553 U.S. 1, 5, 13-14, 128 S.Ct. 1511, 170 L.Ed.2d 392 (2008) (<HOLDING>); Frazer v. United States, 288 F.3d 1347,
recognizing refund claim could be barred if there was any valid local limitations law in force when the claim was filed holding that the taxpayer met the claim requirement where the taxpayer first filed a timely letter with the irs that requested a refund and subsequently filed a formal refund claim holding that refund suit for tax imposed in violation of export clause filed beyond applicable period of limitations was barred where claimant had failed to first present timely administrative claim to internal revenue service even though there was little  if any  reason to believe that claim would have been granted holding that claims for a refund of invalid export tax brought under a statute other than  7422 were barred holding that even in a pro se tax suit a timely claim for refund must be filed to invoke the courts jurisdiction