Since we have several products that rank on the same keywords, it is of course difficult to see that we have to pay for each keyword individually. As we know, in the background, the Amazon page for the search term is fetched once, and all products visible on the first or second page are identified and stored. This means that if two products should be tracked with the same keyword, there is no double effort involved. Nevertheless, it is tough to also pay double for this price now. I would find it fair if tracking a keyword were paid for independently of the number of products being tracked since, as discussed, no additional effort arises.