We've only had 10 orphans since the launch of Mazacoin which is just slightly less than 1% which seems to be on par with the other pools. The difficulty definitely has a lot of wild swings to it and the luck of the pools have some to play into it as well. Coinwarz seems to put the number of coins you should earn per day at a best possible scenario at the current difficulty, and can't really take into account pool luck, but I do find that when I put my hash rate into Coinwarz the average over the last 24 hours gets pretty close.
The block explorer will let you see all the difficulties of the blocks, but doesn't chart it out.
http://explorer.mazacoin.org/chain/MazaCoin