So with amazon affiliates you have to wait for the product to be shipped by amazon before you get the revenue. Thats why looking at the daily profit is pretty much irrelevant.
also remember that if the product is being refunded, you'll lose your commission... the commission to begin with is pretty shitty, so with amazon aff unless you have a good amount of traffic [and conversions] youll be wasting your time, remember that and youll be able to play the game better.