Just a quick concern/question

In regards to the newly implemented champion shard system I was just curious about the fact that 3 champion shards can be purchased for 5,100ip therefore making the champion re-roll a potential profit of 1,200ip if you reroll into a 6,300ip champion because as for someone such as myself with every champion up to 6,300ip bought I myself have been using this method to acquire champions. Or is it the trade off that riot is willing to give the free 1,200ip for you not being able to pick the champion that you re-roll into a champion permanent. Just a question! Thanks for answering.