The first thing you must realize is that no hubber not on staff is paid anything at all.
What the deal is - is simple: Different subjects will have different adverts (contextual) attached to them.
If you are like me and like to write about animals - then you should know that those will be LOW PAYING adverts.
If you write about real estate or investing in gold - those will be HIGH paying adverts, but the competition for those sorts of articles will be INTENSE.
So hubbers are not paid directly in any way - the hubs we write draw different types of ads, and the different types of ads pay more or less based upon the subject matter.
Also - a MAJOR thing to understand is that the advertisers who paid to have those ads....they pay more or less on different days and different months.
In November....advertisers are spending because people are shopping - everyone makes more money in November.
In January - advertisers are NOT SPENDING much money, so everyone tends to make LESS in that month.
Nobody is paid any sort of rate - people are either paid per click (with adsense) or paid per impression, and the impressions pay out differently for different subject matter - they are contextual ads, and the subject matter is vitally important in regards to how much the ads pay.
I hope this has made sense and been useful for you.