So, IME, a student's reading level as tested in school can be an inaccurate measure of what a child is actually reading, understanding, and enjoying outside of school.
I think interest level is your most important indicator. What does your child choose to read and stick with? When my oldest was in school, it became my responsibility to keep him in books. The school "assessed" him at the same reading level all year as a 1st grader. Found out later that particular level (4th grade) is just at the ceiling of what the teacher could deal with. He was selecting reading material above that level at the beginning of the year. If the number doesn't reflect what you expect, don't panic. You may want to keep a list of what your child is reading at home or ask if you can send in reading material.
My oldest is just not the best at jumping through the hoop of reading assessment/comprehension. That is a skill he actually could practice - he assesses well above his grade level, but not where we'd expect. He also would do similar things when he was younger like mixing up short words and mispronouncing longer words even when he knew what they meant. He still will do that on occasion. I can tell when he is using vocab he learned reading.
