The dashboard is a simple and high level overview of estimated earnings, which currently does not take into account coupon codes, purchasing discounts, refunds, or any other variations that might have occurred at the transaction level. It also does not track Kobo Plus, OverDrive sales, or audio sales.
In contrast, however, the monthly sales reports that authors can download from our team at My Account > Payment Information on your dashboard come from our Finance department are accurate and match the payments that you receive.