I scored a 19 Bio, 19 Gchem, and 18 Ochem midterm. I took DAT July 22nd and scored a 20 Bio, 22 Gchem, 22 Ochem. The highest KAPLAN score on sciences, including all of the subject tests, full length tests, blue book and cd tests was a 21 Bio, 23 Ochem, 23 Gchem. My average I would say was a 19 Bio, 20 Ochem, 20 Gchem. Hope that helps.
I would say keep taking tests and figure out the wrong and right answers to make sure you have everything down. Anything you are missing should be easily correctable at this point. In Gchem and Ochem, I seriously think the best way to study is to do 1000's of questions, and doing flashcards of Destroyer roadmaps to do well. Bio is a pure read/study area. So keep at it and your scores should go up, and your DAT score should be a little higher, IMO.