I think I've had one student in the last 10 years who truly didn't have any timing problems.
On the other hand, I've had
dozens of students who have told me that they didn't have timing problems...but they did. So you're going to have to prove to me that you really don't have timing issues.
Too fast is just as much of an issue as too slow. "Up and down" timing (where you rush on some to spend longer on others) is a problem, even if you finish the section on time. (This is probably the single largest timing issue that people have and most people who do this tell me that they don't have timing problems.)
The long sequence wrong in verbal - when you looked at the problems afterwards, were they truly too hard? Or did you make some careless mistakes? There may have been a mental stamina issue going on. And that, by the way, can stem from timing issues - particularly when you make the choice to spend more time (= more mental energy) on certain earlier problems in the test.
So let's dive in and figure out why that score is dropping. First, read these two articles:
http://tinyurl.com/executivereasoninghttp://tinyurl.com/2ndlevelofgmatThink about how what you've been doing does and doesn't match up with that and how you may need to change your approach accordingly.
Then, use the below to analyze your most recent MGMAT CATs (this should take you a minimum of 1 hour):
http://tinyurl.com/analyzeyourcatsBased on all of that, figure out your strengths and weaknesses as well as any ideas you have for what you think you should do. Then come back here and tell us; we'll tell you whether we agree and advise you further. (Note: do share an analysis with us, not just the raw data. Your analysis should include a discussion of your buckets - you'll understand what that means when you read the last article. Part of getting better is developing your ability to analyze your results - figure out what they mean and what you think you should do about them!)
Oh, and most important thing last: I can't tell you how to get "at least" a certain score in a specific timeframe. Nobody can force that. Decide right now. What's most important to you: taking the test in 3 weeks or scoring at least a 680? If the latter, then you may or may not be taking the test in 3 weeks, depending on what happens as you try to diagnose the problems and fix your trajectory. You need to both figure out why your score is stalling out and take the necessary steps to fix it and go back to lifting your score. I'd say there's some chance you'll be ready in 3 weeks but it's more likely that you're going to need to give yourself a bit more time. Don't stress out - you can reschedule for only a $50 payment as long as you do so more than 7 days in advance of your scheduled test date.