Answer is on the middlecoin.com main page. Just calculate rejected over accepted MH/s as a percentage and it will come that percentage is raising going down the table... 
No it doesn't , no it isn't.
if you plot a moving average against that data there are some small hash rate miners around 200th on the list getting better rejection averages than in the top 50. its dynamic and mueslos
graph shows what going on nicely.