Talked to a guy that used to be on the board of admissions, and is a grad, and he said the real reason they do it is to make sure you follow through at the very end of high school and continue to achieve excellence. That being said, he also told me if you have high grades usually, and you slip up or struggle with a certain subject, it is no big deal. The only problem is when you start to make a D or lower. But, this was said to me, with a 4.0 GPA. So if I make a C, then it is no big deal, but if someone who has a lot of C's, it effects them a little more in the grand scheme of things. So just continue to work hard, and don't stress it. But USMA doesn't like slacking. Finish the job!