The important part is Ayanokouji asking to himself, which Kushida is the real one, because it goes both ways, and is the real beauty of that scene.

1) Kushida asks him if he likes girls like Horikita (i.e. manipulative, secretive, driven, cold)
2) She leaves the phone there. It wasn't forgotten.
3) She walks far away, striking his curiosity. Then gives him all the major points that she sees in Horikita.

So, Ayanokouji correctly asks himself, Which of the two Kushida's is the act? Is her perky face the act, or is her bitchy face the act just for him so she can steal his attentions from Horikita? Is her real personality somewhere in the middle?

She's manipulative for sure, she has absolutely been using her body to assist in getting what she or what others want. Ayanokouji recognized that, and she clearly appreciates it, though I'm guessing she doesn't like being left in the dark. He's clearly been hatching plans with Horikita that don't include her in an aware role, and she doesn't like it. She had the third highest points in the class, probably because she was getting others to buy her things, or even from other classes. Now she has the most.