Don't view your Kaplan final or any other exam for that matter as an accurate inidicator of how well you will do on the real deal. Honestly, a lot of people are all into taking exams and more exams. Granted it will help somewhat, but what is more important is that you learn the material. Kaplan has thorough answers to all exams. So you should focus more on learning rather than taking an exam and getting a number. I remember the midterm I only finished 20 problems in math and just bubbled in random answers for the last 20 and got a 23!! Am I going to get that on the real think, maybe, but most likely I just got lucky. I know people who never took a practice DAT and they got a 20+ on all sections. I also know people in my Kaplan DAT class that did good on the tests 18 + and ended up with a 16/17. So it doesn't really matter what you are getting as long as you understand the material.
I didn't even take the DAT final, but just brought it home since I knew that it really didn't matter what I would get on kaplan, but the real deal is what will matter. As long as you know everything on the practice exams I think you would be fine.
The only good thing practice tests are good for is pacing for the PAT and Reading.