Wow... So, for all the blocks that are over 500%, no one gets paid for the work their miners did over the 500% mark?
That's disappointing if you're right.
Sorry - that's the way it works on every PPLNS pool.
If you don't find a block during the LNS period, you don't get paid for those shares.
PPLNS = Pay Per Last N Shares - if the N in this case is higher than the shares between the last block and this one, you don't paid for it, even if you had shares.