Frank O Connar 2ho is the lead creative designer for the Halo franchise already confirmed they shipped less Halo 4 Limited Editions then either Halo 3 or Reach.
Higher revenue with a lower SKU price means 1 of 2 things.
A. Halo 4 sold more copies than any Halo to date.
B. MS is counting something else in Revenue they didnt with other versions of Halo.