When you cast limited wish spell, a genie appears and dialogue window appears. I can have a repeatable wish or one time wish. But I noticed that you can wish a one time wish more than one time? What's that? (I memorized two slots and cast it two times?)

A one time wish means you can select any of the items listed once and once only. You can still cast a one time wish again, but the previous wish will no longer appear on the list.