Overall rank is determined by the average of your ranks, not how much money you spend. In your situation Dav would fall from number one, because while his defense rank would still be high (Even though I just took number one defense ^^) his average would be higher, causing him to be a higher rank. Obviously you don't need an average of 1 (Which would mean youre number one in all ranks) but you do need high ranking score for all stats. For example when I was number one I was ranked 2, 1, 2 and 1, which averaged out to 1.5, and later was 4,3,2,1, which averaged out to 2.5. At both points I was number one because my average rank was lower than anyone elses.