There are a couple of different "ideas" here, so I'll give you some information/perspective on what I think will help you get a better understanding about what you're asking.
First off, a "700" currently represents about the 90th percentile overall. You can actually earn a 700 on Test Day in a variety of ways, so you should NOT think of this as "earning a 700 in Quant and earning a 700 in Verbal."
Second, percentiles vary, but Scaled Scores do not. For most Test Takers, a Q49 is the highest that they'll ever score in the Quant (even though some will score higher) - it's a fantastic performance, but as a percentile it's been slowly dropping over the years (these days, it's right around the 81st percentile - which makes it "look" like it's not amazing, but it REALLY is). This is meant to remind you that percentiles change based on how everyone else is performing, so you shouldn't worry too much about that. Look at your Scaled Scores and any silly/little mistakes that you're making - the GMAT will give you the score that you EARN - the percentiles are just to show you where you are "in line."
Third, the scoring algorithm on the Official GMAT is far more complex than you realize. There are a number of factors that will impact your score, so focusing on "700-level" questions is a rather limited way of trying to improve. At that scoring level, the GMAT becomes really "sensitive" to silly/little mistakes, so you might find it more worthwhile to take a good look at every question you're getting wrong, figure out WHY you're getting those questions wrong and then focus on fixing all of the little things first.
GMAT assassins aren't born, they're made,
Official Guide 2016 Question Breakdown:
GMAT Club Verified Reviews for EMPOWERgmat & Special Discount
EMPOWERgmat Podcast - A Wild Secret About The GMAT Algorithm