My sales rank is rising, but no changes (sales) are being posted on my reports page. I know, with KU, that sales wont be posted until a customer reads 10%, etc., but do sales rank numbers change regardless of if they've read 10% or not?
As I understand it, your book's rank can change if books below yours or above yours in rank start selling a lot more or start selling a lot less. (The mechanics of how ranks change is more than my mathematically-challenged brain can handle but I've heard other people say that.)
This is true, too. In fact, that's why ranks are constantly changing. It also explains why occasionally a rank can drop significantly without any sales. The KU downloads are a significant hidden variable because they affect rank immediately, but you may not know about them ever (those never read to 10%) and the others you may not know about for several days (or weeks).