CAT 6: 580 (Q45, V25) - a couple of days ago, I am almost sure I got much harder questions than on CAT 5, is this normal?
No, each test pulls from the same database of questions and is completely adaptive - it chooses based upon your performance on the test.
It's possibly (likely, actually) that you *felt* certain questions were easier or harder based upon your individual strengths and weaknesses. For instance, you might be scoring at the 60th percentile in a section, and so be given a Coordinate Plane Geometry question. If you love these, you'll think, hey this is easy! If they're a big weakness, you'll think, ugh, this is so hard! But the difficulty level relative to the overall population is still 60th percentile. :)
On your last two tests, Q is solidly in the 40s. Verbal, on the other hand, is fluctuating - you've gotten a couple of scores in the low 30s but your most recent was 25. Why do you think that happened?
Use the below to analyze your most recent MGMAT CAT(s):
http://www.manhattangmat.com/blog/index ... ice-tests/Then come back here and tell us the results of your analysis. (Note: do share an analysis with us, not just the raw data. Part of getting better is developing your ability to analyze your results - figure out what they mean and what you think you should do about them!)
Should I reset the tests and try it again? Will the score be inflated?
You can do this yes. The score could be inflated if you see repeated questions - but there's no way to tell in advance whether that will happen.
Follow these guidelines to minimize the chance of artificially inflating your score via question repeats. First, anytime you see a problem that you remember (and this means: I know the answer or I'm pretty sure I remember the answer, not just "hmm, this looks vaguely familiar..."), immediately look at the timer and make yourself sit there for the full length of time for that question type. This way, you don't artificially give yourself more time than you should have.
Second, think about whether you got this problem right the last time. If you did, get it right again this time. If you didn't, get it wrong again. If you *completely honestly* think that you would get it right this time around if it were a new question (even though you got it wrong last time) because you've studied that area and improved, then get it right this time.
The new GMATPrep 2.0 has the new test structure (one essay + integrated reasoning), so you definitely want to be practicing with that. The Q and V question databases are largely similar to the old one, but you took those 4 months ago, so it's likely that you've forgotten most or all of the questions that you saw.
Note on practice CATs in general: Practice CATs are really good for (a) figuring out where you're scoring right now, (b) practicing stamina, and (c) analyzing your strengths and weaknesses. The actual act of just taking the exam is NOT so useful for improving. It's what you do with the test results / between tests that helps you to improve.
In general, taking a test more than once a week is a waste of time - and, really, taking another test before you have substantially dealt with whatever major weaknesses you discovered in the last test you took is a waste of time. That can often take 2, 3, 4 weeks.
Re: your admissions questions, I really don't know. :) My expertise is strictly limited to the GMAT. We do have a folder here called Ask An Admissions Consultant - ask them what they think! (Though nobody is going to tell you "sure, you'll get in with that score!" because we can't really tell for sure. :)
You may want to buy other tests, but first I would try re-taking an MGMAT CAT and seeing whether you recognize a ton of questions. But remember my note above about not taking too many CATs. If you're actually improving substantially between tests, then you're less likely to be pulling from the same difficulty levels in the database, which means you're less likely to see the same questions...
If you discover that you remember too much / are seeing too many repeats, then try 800Score.