: This chart seems to indicate that Halo 4 is performing better. The only
: reason Halo 3 has sold more, is because it's been selling longer. You can
: see over the respective periods since their launch, Halo 4 has done
: better. Hence, the best selling* blurb I guess.

Did you read my post? This is exactly what I said.

Halo 4 sold more copies than Halo 3 during their first 7 months on the shelves.

This is hardly surprising because of the Xbox 360's MUCH larger install base in Nov 2012 vs Sep 2007.

Even then, if you look at the trend and play around with the other perspectives and scopes, Halo 4's sales are declining at a faster rate than Halo 3. It will be underneath H3 soon enough.