Arco Book harder than normal?

<p>I've taken all of the practice tests in the Real ACT prep book, and I know where my strengths and weaknesses lie: I've gotten consistent scores of 35-36 for science and reading, but I bomb math and english. However, after studying elements of style I took the practice test that ACT has on it's website. I got 5 wrong there, which was a huge improvement from the 9+ wrong I was getting before. I also improved on math. Then I took a test from a Kaplan book and got 4 wrong in English. So I was feeling pretty confident that I could get my goal of 34. However, I then took a test from the ARCO prep book and I got 13 wrong on English. I was just wondering if the ARCO book is like barrons and is harder on purpose or if I just bombed it?</p>