My point about the envoy suites is that AA has a limited number of domestic flights on internationally-equipped A330's. These have sleeper seats and in some case "premium economy" seats comparable to domestic first class. But they don't have a separate pricing structure for them, so the sleeper seats are priced as first class, and the PE are priced as MCE. So if you purchase an "F" seat on these flights you're getting a much bigger bump in product. So I'd assume many more people (myself included) will purchase these seats, where they might not otherwise buy an F ticket.