+/- 50 points is within one standard deviation, so yes, that's pretty typical.
Two things concern me:
(1) You mention timing problems in quant. If you mess up the timing badly enough, that can KILL your score - and the real test is a lot more nerve-wracking than practice tests (because you know the real thing counts). Don't rely on the idea that the real test is going to be easier. It's true that many people think our quant can be a bit harder / more computation intensive, but you also know that the practice tests don't count. If you're also struggling with timing, you could be setting yourself up to have a timing meltdown on the real thing - we don't want that.
Read these two short articles:
http://www.manhattangmat.com/blog/index ... to-win-it/http://www.manhattangmat.com/blog/index ... -to-do-it/Then take a look at this longer time management article. Note that it often takes people a good 4-6 weeks to fix timing problems - so you may need longer than 3 weeks.
http://www.manhattangmat.com/blog/index ... nt-part-1/(2) Next, your verbal score is really fluctuating. Why do you think that is? Did you take these tests under 100% official conditions, including essay and IR? Or did you give yourself any kind of advantage during that second test that might have made you less mentally fatigued than normal during the verbal section?
Finally, to your last question - when you start talking about 750+, there's nothing anyone can tell you about how much time that might take. 750+ is a whole new ballgame. Some people might take 3 weeks, some people might take 6 months (and that's assuming, of course, that they actually get there - only 2% of people ever reach that level).
Most people (who are eventually capable of hitting 750+) would need more than 3 weeks to go from where you are now to 750+. Start thinking about this: is the timeframe more important - you have to take it in 3 weeks, and you'll just be happy to push as high as you can in that time? Or is the score more important - you'll take more time, if needed, so that you can have a better shot at hitting that level?
Read this:
http://www.manhattangmat.com/articles/7 ... erence.cfmAlso, the timing issues you mention on quant just got infinitely more important - it's impossible to hit 750+ if you have any timing issues that are more than very minor. Given that it typically takes a good 4-6 weeks (of daily practice) to fix timing issues, again, we're probably looking at more time if you do want to continue to go for that super-high score. Let me know what you think.