Yeah you are right if they mine 30 blocks per day it is near $25500. But from time to time i get 48406 to be #1, 41921 to be #2, 1798 #3, and the pool hash rate is the same 9,900+ GH/s. Is it possible that the first 4 are scam?
It sounds like you're refreshing the Hall of Fame when it's being updated. The Hall of Fame on BTC Guild actually stores the rank for all ~72k users. It flushes the entire table and loads it with new data every few minutes, so if you reload it while that's happening you won't be seeing the complete rankings.