I am going on a whim here, but I believe highscore rankings might change once a month, that is the first in each month. The reason it might not have changed could be that there have actually been no change to it.
I don't think that will happen because of the launch of Armor Games version 3. The admins probably don't have the time to renew the monthly rankings seeing how much work they have to do for everyone that expects the launch mid-late this year.
I've seen it changing in the past few months, but only to accommodate those users who have a sudden surge in points. So my theory is that it's mostly spammers who end up there now. Wasn't like that last time though.
Thanks guys for not answering what he asked about. Highscores =/= On site ranking. Yeez, I would have thought of all your vets, at least one of you would read more than the OP in a four post thread. Answered.