1)
The passage about the discount says, that you only get 1 point of refresh back, if the item is difficult to detect and can be concealed, which is definitely the case with a belt buckle.
2)
I don't see a problem with a refinement IoP, only one thing: an IoP should probably not be used for focus item slots, because those have to be items by definition, so you would simply get refinement for free by making your focus items an item of power. I would have no problem though, with a ring that provides fire if you already have evocation (and probably provide a fire specialization too, because you would need at least 2 refinement on the item, to get the discount).
I don't have a problem with an IoP for Crafting. Only one thing: if you lose the IoP, you still have the enchanted items you made with it. But once you use those items, you have to recharge them, and for that you don't have your IoP, so you would have to decrease the item accordingly. And the IoP should probably be something that is actually used to create the item, like a hammer, a carving knife, something like that.