what is more, I do not think bschools are ranked according to top20 or top30. There is huge difference between those programs that just make the top** list and those, say, H/S/W, magic seven, and a handful of elite schools that are always prestigious.
In this sense, if you have 750+ GMAT but average background in other areas, you are likely to obtain nearly full scholarship from some top20 school(s), but no competitive edge in others.
As you will find in the successful cases in CD, your background is enough try top10. You are also in a position to get scholarship from, say, Emory, which likes high GMAT.