There are several variations or add-ons for Affiliate Pro, but it is not apparent whether each is a version or add-on.
The phrase "all features of the Affiliates Pro plugin are available" is in the description of several Affiliates Pro Integration Packs, which implies that maybe it is not necessary to buy "Affiliates Pro". Or maybe it means that Affiliates Pro is also required, but the Pack does not interfere with AP's features.
But if each is a standalone version, it is not apparent whether they can be combined -- can both eShop and PayPal Packs be installed? Can they all be installed, or are some mutually exclusive?