At some point it evens out, though maybe not until HS or college. And take some of these reading levels with a grain of salt...middle kid was evaluated at a junior in college to graduate level in reading in 8th grade. What does that even mean? She should read PhD theses? I think not.

Did the school do anything special for her? No, but I don't think she has been damaged for life. Let the kid read outside school at his/her level. At some point, as they get older, they will be in with others who read/comprehend at that level and it will be better.