I think you are confused by what superscore means. Say you took the ACT four times. These were the math scores, one from each test session, in chronological order: 28, 29, 34, 30. These were the science, one from each session, in order: 32, 28, 30, 35. Reading: 30, 24, 30, 32. English: 32, 31, 29, 30.
To superscore means to take the top subscore in each category (Math, Reading, English, and Science), regardless of which test session it was, and combine them together. In this case, with all four hypothetical test sessions taken into consideration (ie they were all reported to the USAFA), this candidate's superscore subscores would be: math 34, science 35, reading 32, English 32. So they give you the benefit of the doubt and take the best score from each category regardless of the test session in which you took the test. It's just another way to help candidates out.
I think that they also superscore the composite scores.