Hi Louis14,
A 680/Q48 is a fantastic Score, so while I would certainly follow the suggestion offered by the Admissions Expert you referred to, if you have a strong Overall profile then this Score might be enough to get you into your first-choice School.
Based on your deadlines and Score goal, it would help if you could provide a bit more information on your timeframe and studies so far:
1) What 'brands' of CATs/mocks have you used so far? On what dates (or approximate dates) did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
2) For your next attempt, are you planning to take the At-home GMAT or are you planning to take your GMAT at a Test Facility?
3) Going forward, how many hours do you think you can consistently study each week?
You might also choose to purchase the Enhanced Score Report. While the ESR doesn’t provide a lot of information, there are usually a few data points that we can use to define what went wrong on Test Day (and what you should work on to score higher). If you purchase the ESR, then I'll be happy to analyze it for you.
GMAT assassins aren't born, they're made,
Rich