If what Argh_college is saying is true, then Halo 4 is undertracked in the USA by at least 400k.
According to vgchartz, halo 4 has only sold 4.6m in the USA so far...
:0
My prediction threads:
Wii U will sell under 40m units (made on 14th September 2012)
PS Vita will sell under 20m units (made on 30th September 2012)
Wii U will sell under 7m in 2013 - I was right