I haven't taken the real DAT yet but I was letting DAT Achiever freak me out to an extreme. I would take their practice tests, do just awful and get myself all worked up for nothing. I actually called the owner because I was doing so bad, and asked for advice. He was really nice. He went over things with me, told me ways I could improve and assured me that the real DAT is a lot easier. I acually went against his advice and opened up the rest of the tests I hadn't taken so I would stop freaking myself out. I then studied the problems I didn't understand.
I am now actually greatful for DAT Achiever tests and would highly recommend them. I think it helped me a lot. I just wish I wouldn't have let it get me so upset so take my advice and don't let DAT Achiever upset you like it upset me.
This weekend I took the 2nd Topscore practice tests, and I made Bio 19, Chem 18, OChem 20, PAT 23, RC 23 and QR 21. This has gotton me really excited, and I am beginning to realize how a positive attitude makes a huge difference. So....take my advice and use DAT Achiever as a study tool only. Also, I think his PAT portion is the best. I was doing just awful on this section. Use his practice PAT's and take those like the real thing and then go back and see what you did wrong so you can improve.
Good luck and hope this calms your nerves. For now, I have got to get off of this website and wrap things up for my real DAT that is is 7 days!