Naish 2011 merges All Terrain in Session in larger sizes - 2 years ago

I see that Naish 2011 has merged the All Terrain sail into their Session lineup in larger sizes (i.e. 6.2 and 6.7). It's said that these larger sizes have been optimised for Bump and Jump but does anyone know how these particular sizes have been tweaked and how they would "feel"? I thought the All Terrain had quite a lot of bottom end grunt for larger riders (which I like but this isn't