Hello, I personally did 6 practice tests (Kaplan, ADA 07, ADA 09, Topscore 1-3).
I was also doing mini-tests with CDP, CDR, destroyer, etc... during that time.
I kinda regret not using Achiever due to limited amount of time that I had to study and take the DAT. Seems like all the people who got great scores used Achiever to study and practice for the real thing.