Hi Gagan,
GMAC has publicly stated that the Official Score that you earn on Test Day is generally within +/- 30 points of actual ability. Assuming a similar 'swing' in how your CATs function, your various CAT score results - along with your Official Score - show that you essentially performed in the same general range each time, although your range is a little bigger than most (re: 680 +/- 40 points). You handle certain aspects of the GMAT consistently well, but you also leave yourself open to making certain types of mistakes.
If - after reviewing your overall profile - Admissions Experts think that you probably 'need' a 710+ to get into your first choice School, then there's a good chance that they are correct. You're close to earning that type of Score right now, but you CANNOT afford to be 'bored' about this process. If the thought of earning an even higher GMAT Score, getting into an outstanding School, earning a valuable degree and having a better career because of it isn't enough to get you excited, then I'm not sure that anyone has the ability to properly motivate you.
I can tell you that the Verbal section of the GMAT is as consistent and predictable as the Quant section is, so you CAN train to score at a higher level in that section. However, Verbal questions have no 'safety net' - meaning that if you make a little mistake or miss a vital piece of information, then you will convince yourself that one of the wrong answers is correct (and not realize it). Proper note-taking is essential for all RC and CR prompts and thorough knowledge of grammar/idioms is essential for SCs. You can learn how to do all of that work in a more effective and efficient fashion, but the "will power" to keep working and making smart choices is all on YOU.
If you want to make all of these dreams come true, then this IS doable, but you have to commit to a specific study program and hone the necessary skills to earn that higher Score.
1) What application deadlines are you facing for ISB?
2) Going forward, how many hours do you think you can consistently study each week?
GMAT assassins aren't born, they're made,
Rich