<p>I believe the way it works is that people take the Math IIC test understanding that it is the test that looks better to colleges. A lot of people take it not knowing what they're doing. They take the test, do badly, and the curve shifts over in everyone's favor. The Math IC test is easier, more people do well on the test, and it becomes a comparatively easier test, thus weighing the overall curve to the high end, and making it harder to get a good score. This is just what I've come to understand of it, and I might be wrong.</p>