Hi sarthakaggarwal,
To start, a CAT is really a 'measuring device' - when used correctly, it will give you a realistic score and help define your strengths and weaknesses, but it will NOT help you to fix any of those weaknesses. To raise your scores, you have to learn the necessary Tactics and put in the proper practice and repetitions. The CAT will show you whether your studies are helping you to improve or not. In addition, the process of taking (and reviewing) a CAT requires a significant amount of energy and effort - and takes time to 'recover' from. This is one of the reasons why you typically shouldn't take more than 1 CAT per week - and your last CAT should be taken about 1 week before Test Day. Going forward, you really shouldn't take more than 1 FULL CAT per week.
In addition, you have to be careful about confusing "quantity" of study with "quality" of study. I've never asked anyone to study 30+ hours a week - and while it's great that you might have the available time to study that much, with that number of study hours, you would run the risk of 'burning out' before Test Day (and that is something that we want to avoid). If you are going to try to study that much, then I suggest that you take one hour "off" for every two hours of study. For example, you could study for 2 hours, then stop for an hour, then study for another 2 hours, then take an hour off, etc.
Silly mistakes can almost always be traced back to a lack of proper note-taking (re: you're trying to do too much work "in your head" and/or what you do choose to write down is disorganized or leaves you open to making a mistake). You might have the necessary knowledge and skills to earn a 700+ right now, but you're not doing the necessary work during the Exam to earn that type of result.
Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
1) How long have you studied? How many hours do you typically study each week?
2) What study materials have you used besides the books that you mentioned? What “brands” of CATs/mocks have you used?
3) On what dates (or approximate dates) did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
4) When are you planning to apply to Business School and what Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich