Amazon is effectively cost-controlling your book, experimenting with different numbers to get the sale—but this does not mean you’re going to get paid less. So, for instance, you might be selling your print book for $15, and Amazon is discounting it at their usual 20-30 percent off the list price. But then you’ll see that one day—maybe for a day, maybe for a week—that they are selling your book for $9. In these cases, Amazon is undercutting their own profit, and you get the same payment from them regardless.