You're not doing anything wrong, it's the same for all of us
I wouldn't trust any pools that claim they have a 0% fee, I mean would you do anything for free? Some of them steal a percentage of your good shares.
Some other things that you need to be aware of are:
+most online calculators are a bit off
+you need to take into account that you're not using a fixed difficulty so, a variation in hash rate will occur
+block effort is also variable