I think part of Kaplan tests are a scare tactic. From scoring horribly on one of their tests, it makes you feel like you have to study like crazy because you know nothing. Then, once you do and make a great DAT score, you tell everyone that Kaplan worked for you. Kaplan says that their material isn't all you need. Kind of a disclaimer.
According to my kaplan instructor, the kaplan integration workshops are much harder than the actual test. i remember having to do 5 step dimensional analysis and calculations that would definately require a calculator. use it strictly for mastery of the material, not so much a gauge of how hard the test is.