I can see a directive that says that hitting the top of the grade/GPA index alone isn't enough, because BYU wants to save some room for some students with a slightly less polished academic profile who excel in other areas. For diversity of the student body, BYU could pass on a few 5.0 GPA / 36 ACT kids who seem like they have no personality and no drive.

But if a kid ticks every single box (grades, test scores, history of service, extracurricular and leadership activities, notably challenging background) and is STILL denied in order to admit a different kid with nearly the identical non-academic stuff but lower GPA and ACT/SAT, then that seems messed up.