I guess it depends on the test, some say it is similar and other say different. I say different. I was scoring 22-23 on Topscore and ended up with a 17 on the real thing. The DAT was different in that it was a lot harder for me to find what they were asking about in the passages. I would have a question on a cell membrane for example, but instead of the answer being in the paragraph about cell membranes it was somewhere else in the passage where they referenced it extremely briefly.
People complain about the tone questions but I thought these were the easiest, most of them you can figure out by reading the last paragraph. I am not retaking the test because of the RC and the QR. I got 17's in both but did well enough in the sciences to bring my AA to a 19. I just don't think I could do better next time and so I am just not gonna risk it.
If you have any more questions you can PM me.