Pub. L. 109–163, div. A, title VI, § 614(c), Jan. 6, 2006, 119 Stat. 3293, provided that: “Section 910 of title 37, United States Code, as added by subsection (a), may apply only with respect to months beginning after the end of the 180-day period beginning on the date of the enactment of this Act [Jan. 6, 2006].”