The real thing seemed SLIGHTLY easier to me. It has less tone based questions and more details. If the tone questions are your problem, you're probably good for 18+ on the real thing. If your problem is timing you should practice different strategies. I skim the passage first to figure out the structure (maybe 2 min). Then i go to the questions. If i come across a question I can't easily find, I write down question # and a key word. When I see the answer to that question (while answering another question) I write down the paragraph and go back. I did 3 CDR tests 18,21,23. On the real thing I got 24.