I don't think CDP is representative of the real test in terms of difficulty. I got about the same site on my CDP tests as the real DAT, but there's no way I could have gotten my 25 without Achiever. In my opinion, do CDP until you're comfortable with the PAT but then go to Achiever. My achiever scores were lower, about 19_21 I think, so the spring may be off but the material is very representative of the real PAT. I have a breakdown in glimmers list if you want to check it out