Within 60 days of the first exercise of the authority granted in section
5211
(a) of this title, but in no case later than December 31, 2008, and semiannually thereafter, the Office of Management and Budget shall report to the President and the Congress—
Beginning with the second report under subsection (a), the Office of Management and Budget shall explain the differences between the Congressional Budget Office estimates delivered in accordance with subsection (b) and prior Office of Management and Budget estimates.