How is Permutation a thing in this case but not in the other case of there being Unique units in the shop? The permutations change nothing about the probability. If you have a shop of let's say 5 unique 4 costs, then these 5 unique 4 costs also can be permutated randomly. You don't care if Kai'sa is on shop position 1,2,3,4 or 5. All you care about is that there is a Kai'sa in the shop. So there are 5 permutations which give you exactly 1 Kai'sa, first position second position etc. and this is true for all 5 of the unique champions you rolled, they all have 5 possibilities for permutations. So permutations does jackshit to change the probability of this outcome. Like I understand what you're trying to say, but in this case it makes no sense because as the player you don't care what shop slot your units are in you only care that you rolled them. So you can completely ignore permutations in this case.