Whats the difference between C and E?

Hi Tyler808, C is saying that Beck assumes the estimates would stay the same from week to week even if the estimates were not accurate. E says that Beck ignores the possibility that the estimates could stay the same from week to week but also be inaccurate. C suggests that Beck makes a false assumption (which he does not) that if the estimates were wrong they would be consistent. E suggests that Beck wrongly ignores the possibility that consistency does not equal accuracy, and that the program could be consistently wrong.