I'm in the process of retaking a few courses, including a semester of introductory biology. My university recently overhauled its introductory biology curriculum, and the general course no longer exists. There is a new course with a different title and number which covers so much of the material that you can't receive credit for taking both.
I understand that AACOMAS calculates only final retakes into your GPA, but how similar do the courses have to be for them to accept them as retakes?