Apple sends Blurb payment for iBooks Store ebook sales approximately 30 days after the end of each month. We then process your Apple payment with the next batch of Blurb payments. We make payments after the close of the month that you reach our minimum payment threshold. Here's more information about when we pay out profits.
Essentially, you get paid for your iBooks Store sales 60 days after the sale, assuming you meet our minimum payment threshold. So, if you sell books in the Apple iBooks Store in January, you would receive payment for that via Blurb in March.
Your Blurb book sale metrics will not include Apple iBooks Store sales.