I just looked at my Chemistry matches, and women who were rated higher before are now rated lower. Before when? Things they are a changin' Op. Give it time, and the list will change again.
Was a change made as to how the number is calculated? Nope, more likely the change was in who signed up.
As an experiment Op, change either the distance, or the number (of results) regarding who shows up in your "chemistry" results. You may get "introduced" to some neat women that normally don't show up in your regular searches.
And hey, thanks Op, you just introduced me to the Sarcasm Society... much obliged!