A 7 year old that understands maths like an average 14 year old, while rare, is going to be much more common than a 7 year old that understands Shakespearian poetry like an average 14 year old.
A typical kid will be at different percentiles for different endeavors, but even if they were at exactly the same percentile for everything, that same percentile would correspond to different levels of advancement (in years) for different endeavors.
In other words:
Asynchrony is normal.
Yes.
My DD was the oddball there-- her comprehension and reading level always seemed to be more or less in sync, but then again, she read relatively late (at least in this cohort), too-- she wasn't reading until she was four.
But yes, she
was that unusual 7yo Shakespeare fan. It's
very hard to accommodate-- and the kids are very very VERY rare.
It may be a temporary developmental thing-- as squishys notes. Because my DD wasn't reading high school level (and beyond) until she
was nearly six, I have no idea whether she WOULD have been asynchronous if she'd been decoding at 2 or 3.
I also second the recommendation to just TALK about fiction with your child. Go beyond the summarizing and retelling to questions about WHY, and judgments about characters' actions or statements.
"How do you think that Little Bear is feeling right now?"
"Why do you think he is happy at this part of the story?"
"What do you think Jane is thinking about?"
"Do you think that was a good idea?"
"How would you solve this problem?"
