If they had kept both exchanges as they were you would have the following broken rep grind. Not saying it's efficient, but it would definitely be broken. 50 materials --> 5 marks, 25 rep 10 marks --> 20 materials 100 materials --> 10 marks, 50 rep 10 marks --> 20 materials 80 materials --> 10 marks, 50 rep 10 marks --> 20 materials 80 materials --> 10 marks, 50 rep And so on. Keeping it, the system would've created a broken rep grind.