When you go to your My Scenes area, there is a column that shows you the number of times each scene was sold. I had to disable this column for a while, while I reprogrammed the code that makes that number tick (it was slowing down other parts of the site). So your sales stats were stuck at 0, or wherever they were on July 28.
I've finally been able to finish up work on that, so your stats should start being accurate again (even retroactively), starting this evening.
Don't forget that you can also go to your Sales Stats page and adjust the date range and even specify an individual scene ID, and get all the customized sales stats you want on it.