Board Thread:Versus Debates/@comment-142748-20150410212019/@comment-26127155-20150412081819

Edo's have been shown to hold back a certain amount of their power during combat. The third Raikage could have instantly moved to his 1 finger technique and blitzed most of the ninja alliance, but withheld the technique until he needed it later on. The other kage could have spammed their most powerful jutsu but generally tried to hold back, since Kabuto gave them a certain amount of control (as long as they were doing their job, than he was fine with how they went about it).

This easily allows Itachi to hold back (since we don't know how much Kabuto really knew about Itachi) as Kabuto would not know if Itachi was fighting as his best potential or not. Itachi could have spammed his other techniques (tsukuyomi, Ameterasu, Susanoo, etc) as well as using shadow clones which would spam these techniques as well.