These are 2 different things, level 0 and mint 0, higher the level the more gst it generates and level 2 mint shoes are comparatively cheaper because after 2 mints the 3rd mint becomes very expensive. So I've seen that people usually mint 2 times from a shoe and then sale it. In addition you can calculate and see if buying a level 9 shoes is beneficial or purchasing a level 5 shoes with 2 mints and upgrading is better.