I strongly believe first 10 questions are very important and play key role in deciding the score.
This is a myth, so your first task is to learn more about how the scoring really does work - otherwise, you'll have a similar problem next time.
I also just want to warn you that everyone who does really well thinks at some point that they didn't do very well - this is because, the better you do, the harder the test feels. If you're doing well, then you're going to get really hard questions (relative to your abilities), so you'll feel like the test is super hard and like you're constantly getting pushed to the edge of your ability. This is true even for people scoring in the 99th percentile - this isn't like in school, where if you were really well prepared, you felt that the test was relatively easy.
Now, having said that, if you had to guess on 6+ questions or left a bunch of questions blank, then that could justify a decision to cancel your score - so I'm not saying you were wrong to do so. But I just want to warn you that you're never going to get to the point where you feel the test is easy. The only time people feel the test is easy is when they're NOT doing well, so it really is easy because they're getting questions that are below the level they can normally answer.
Read this:
http://www.manhattangmat.com/blog/index ... to-win-it/That article links to a couple of others - the Scoring section of our free e-book, an article on Time Management. Read those too.
Once you've thoroughly educated yourself about how the scoring works, you'll then understand the importance of time management. Then you can do the exercises discussed in the Time Management article and learn how to manage / balance your time better across the section so that you don't run out of time. It typically takes about 4-6 weeks to fix significant timing problems.
If you'd like to talk about strengths and weaknesses, or what / how to study, please use the below article to analyze one of your recent MGMAT CATs:
http://www.manhattangmat.com/blog/index ... ice-tests/Then you can come back here and share your analysis with us (not, don't just post all of the data - we want to know your analysis, or what you think it means). Also note any ways in which you deviated from official testing conditions (including skipping the essays, taking longer breaks than allowed, etc.).