All of this has been very well documented in places that authors tend to congregate. (While we have some authors here, MR is more for readers and ebook/ereader aficionados than authors.)
The Digital Reader (Nate the Great's e-reader news/blog) has been noting and publishing the rates for a long time. It's even easy to see how Amazon gets the "per page" rates each month:
$/Page = (Total number of subscriber dollars - Amazon's Cut) / (Total number of pages read)
That also shows why Amazon has to have the click farm scam detection. All someone needs to do in order to increase their share is to get more pages of their books read. Even though the $/page will also go down, they have a higher percentage of pages read so they get a larger piece of the pie. And right now that pie is ~$24 million each MONTH. So, even getting to 0.1% of that in a month would be a very good payout. (Incidentally, the hypothetical cookbook Dr. Drib was talking about would have had approximately that 0.1% of the pie.)
BUT, that also reduces the "fair use" payouts to the authors who are not trying to scam the system. That's the problem and why Misty's original behavior was flagged. It looked like someone trying to take a larger piece of the pie than they actually earned thus cheating the honest authors out of their "fair use" piece of the pie.