For my midterm, I got 18/17/17. It was the first test I took after the diagnostic. I improved to low twenties after that though. So don't worry because you have more tests to work on. I took the other tests out of order: #2,#1,Final, #3, and just FYI, Test#1 is so ridiculously easy, I think it must be an ego booster or something. I got 21/22/22 with a 30 on orgo. And Test#3 is ridiculously hard, so I wouldn't take that last because it definitely messed up my confidence. My results with topscore didn't vary as much as with Kaplan. I ended up with a 20/20/20 on the real DAT, which I took in May. I'm not quite satisfied, so I may retake in August and use Destroyer instead. Oh and Kaplan Bio is way too easy/straightforward, especially the way they ask the question, whereas the real DAT had a more roundabout way of asking questions. For example, I got a 24 on my last kaplan test in bio and got an 18 on the real DAT. For PAT, the only section on Kaplan that might be representative is pattern folding. Definitely use CDP for PAT. I was averaging a 22 on PAT using CDP. I thought RC for Kaplan was pretty good actually. In the review book, I got 22's on all 3 tests, and then you can see what I got for the online tests. Kaplan, however, doesn't do many tone questions, so there are definitely a couple of those on the real DAT. Other than that, real DAT RC is pretty similar to Kaplan.
Here are my results in order: Diagnostic, Midterm, P2, P1, Final, P3, real DAT
TS: 17/18/19/22/19/19/20
Bio: 16/18/19/18/20/24/18
GC: 16/18/21/18/18/16/20
OC: 19/18/18/30/20/15/21
PAT: 17/17/20/22/21/20/20
RC: 21/15/19/20/21/19/22
QR: 18/17/19/21/19/18/20
AA: 18/17/19/21/19/18/20
Again, test 3 was super hard. I took it like 4 days before my DAT. Was not happy.
My advice would to keep going and keep your head up and try not to base your satisfaction with your studying and what you know solely on the practice tests. That can seriously undermine your confidence. After all, the mistakes could have been little things to memorize or stupid mistakes, so make sure you go though your tests and know why you got things right and why you got them wrong. Good luck!