With the cheating you forget what is written, while Isabella made the evaluations of the test. So that they are the right answers, only in the wrong place.
What does the MC think when he finds the cheat sheet? So that they are all the answers to the questions of the midterm exams.
Dawe is not the cheater because he always fails the exams and he wouldn't if he had cheated before.
So who are Isabella's favorites? Ashley, Lily and Derek. Rooster tells us who placed the cheat slip.
Camila@Cammy
@JustAsh Isn't Anthony retaking our classes?
Anthony@BigA
Cammy Yeah. Cathy told me it has something to do with the problem of learning this ability. I don't even wanna learn Math and English.
Conclusion:
I think so Derek got the cheat sheet and memorized it. He is a cheat master. This is how Ashley got the cheat sheet. Only the three of them (Ashley, Lily, and Camila) did the same thing as Derek. They memorized the cheat sheet. Derek, as the cheat master, will have guessed Ashley to do it. They memorized more or less well, that's why they are the right answers but in the wrong place. But Ashley is then with Anthony and so the cheat sheet got to Anthony. But he doesn't want to learn, as you can read in the Rooster Cluck. So I assume that Anthony placed the cheat sheet. Possible so Lily, Ashley and Camila from Anthony knew that, but Anthony certainly didn't tell Derek that.
If the MC destroys the cheat sheet, Antthony, like Dave, will screw up her midterm again.