No, just because he dosesn't have 5 susanoos doesn't mean he can't create a situation where the relatively thick-headed raikage will be hit by ama. The fact of the matter & my point is that situations vary, using sasuke's situation to prove that ama is a non-factor is simply wrong.
He will create a situation where Ay can get hit.
Ay is simple-minded & can easily be provoked. He's a hot-headed fighter & always charges in blindly therefore having itachi create a situation where he disregards ama can be easy. Ay lets himself get angry enough to not only disregard his safety, but even risk his life. Mifune/danzo said it perfectly. [
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] He let's his emotions control him & in the end he only ends up destroying himself.
Against a ninja like itachi, who doesn't wear his heart on his sleeve & can calmly analyze a situation at hand is actually a terrible matchup for ay. Since itachi isn't terribly outclassed in terms of speed/reactions he can set up traps & play mind games via bunshins/crows with ease.
All ay has is speed, if he fails to use his speed correctly then he falls victim to ama. That "reason" you vaguely mentioned can be a variety of different things that itachi can turn into opportunities. You're acting as if every single amaterasu shot itachi uses is going to be dodged, that is based on nothing but the fact that ay managed to dodge it one time & whilst anticipating it & in V2 mode. This is a different fight, with different people, the outcome will not be the same every time that ama is used.