example:

lineup: the common AGK kisame wind main one.

AGK uses her mystery: mystery damage get cut by 50%. mystery triggers the 10 combo of wind main (pure nin), 10 combo of wind main damage gets cut by 50%. the 10 combo + koh trigger the 20 combo of kisame (pure nin) since is the 3rd nin effect, then the 20 combo chase damage of kisame won't be reduced.

itachi fully counters edo hiruzen teams, but beware that for AGK teams is not said at all.

remember that for agk/kisame/wind main teams it's easy to trigger the 10 combo even without using AGK mystery, then could happen that the skilled enemy actually do not fire AGK mystery asap, but waits until 2 nin effects are dealt to you (sharks are pure nin effects, wind main standard attack is pure nin, etc...).

Remember also that dream state can be removed if the enemy owns more than 30 chakra points, condition way easier to be met by AGK teams than by hiruzen teams.

But yes, itachi imposes, very likely, on the enemy to delay AGK mystery, so gives you more time to choose what to do.