Does it matter which banner my customer clicked on?

No, not really. Regardless of how your customer arrives at our store - whether through any product banner or custom link - as long as your affiliate code is on the link, you will get credit. The amount of commission you earn depends on which products the customer purchases, not which banner they clicked on. So even if they clicked on a banner that was in a 15% campaign, if they purchase a product earning 30%, you earn 30%.