Hi prav04,
Unless you have already taken all 6 of the Official GMAC practice CATs/mocks, you have to be careful about seeking out documents that contain all of the Official questions from that software. If you answer those questions, then you will be far more likely to see some of them again later on if you take one of those Official CATs. Unfortunately, seeing even a few of those repeat questions will throw off the Scoring Algorithm and your pacing, stress and energy levels will all be 'better' than they normally would be - leading to an inflated, unrealistic Score result. In essence, you will have have 'wasted' the most valuable practice CATs available - and that's a terrible 'trade off' just to get some free Official practice questions. There are plenty of other sources for high-quality GMAT practice questions, so you should consider all of the options.
GMAT assassins aren't born, they're made,
Rich