Schools fill seats in their program throughout the admissions season with the bulk of the offers going out in the first and second round. There is some debate over whether first or second round is better, but make no mistake, either is better than third round. By the time third round opens up, most seats are filled (schools are under tremendous pressure to maximize their capacity and do not take the risk of "holding out" for a marginally better candidate if they have someone who will commit who has already submitted their application). While there are definitely still opportunities available, in the third round, schools are mostly looking to fill a niche or gap in the incoming class and are looking for a very specific applicant. If you happen to fit the need, lucky you! But odds are, even if you have a very competitive package, you will not make the proverbial cut in the third round because your profile lacks a specific characteristic that they feel will round out the class. Additionally, in the thrid round you are compared not only to other third round applicants, but also to everyone on their seemingly endless waiting list. Hate to be so negative, but especially given your below average GMAT score for top schools, you will likely be wasting your time and money trying for third round at top tier schools, Sorry!