To opt for Olin(WashU) or not

Olin is a good school--certainly within the top 50 of around 400 MBA programs in the US, but indeed as you identify, if you want to land a job with a top consulting firm, it would be easier from a top 20 b-school. Easier, perhaps, from elsewhere, but not impossible to achieve from Olin. Your GRE score is around a 700 equivalent GMAT, so I wonder why your actual GMAT is coming in lower? Having said that, there's not a reason why you couldn't try again this year in earlier rounds with your GRE. I think third round may have been what did you in. Third round is tough for any applicant because at that point, the b-school incoming class is largely complete, leaving very few seats for third round applicants. Plus, at that point you are not only competing against other third round applicants, who are already (generally) very well qualifiied (lots of folks, being scared by 3rd round simply don't apply, leaving only top applicants), but also you are competing against everyone on the WAITLIST who have been sitting there trying to get a coveted seat for one, two or more rounds. Check for schools in the top 20 for which you think you have a good cultural and academic fit, and see if any offer early admission options, which tend to be a little more lenient in the application process. You might also consider getting some consulting help to analyze and see where in your application you could improve for next year.