Each and every point, including those located farthest from the center, is a standard-precision cross-type sensor ... with effective maximum apertures of f/5.6 or faster.
http://www.usa.canon.com …ArticleAct&articleID=3049
so from the sound of this, 2.8 or faster gets you high precision diagonal center sensors, but they are all cross type with f/5.6 or faster lenses.
Ahhh, good catch. I keep getting Canon's marketing confused. On the 1D bodies the outer AF points turn into high precision when used with f2.8 lenses. Nice to see that the 7D is cross type standard precision which is much better than before for the 1.6 bodies and even the 5D II.



