Personally my largest problem with AP tests is the reliance on multiple choice. Even though there is a free response section, half of the score still comes from multiple choice questions. For most subjects I'd say that the free responses are by far a more accurate gauge of subject knowledge. It is much harder to fake your way out of a free response question with various test taking and guessing strategies. Additionally, not only is it easy to guess your way out of multiple choice questions you may not know, but it is also much easier to make simple mistakes as someone who knows the material and get something wrong, the AP has no idea why you got a multiple choice question incorrect. In contrast, free response favors a student who might be having a rough day / test but knows the material. They may not get all the points, but it is likely that their response will still demonstrate their knowledge. I am taking 3 AP exams this year, CS, Phys C, and BC and even though I have been coding for years and have never actually taken BC (I took AB last year and have studied the rest over the course of this year) CS is my most difficult practice test. This is because I tend to misread multiple choice questions and am not great at standardized testing so even though I get 90-100% on the free response every time, it is easy to get a run of multiple choice questions wrong. Running though code by hand and answering multiple choice questions is a very different skill set from real coding, and it is frustrating that this skill is weighted as 50% of your AP points. Of course knowing the material helps, but after a certain point, reading errors and knowledge gaps become hard to distinguish within a multiple choice test. The low cut offs merely indicate the college boards acknowledgment of it. They've chosen to give everyone the benefit of the doubt that the wrong answers were careless rather than knowledge based and as such most schools simply end up having to retest everyone anyways.