Just following-- my DS7 is in a similar boat. His comprehension and decoding skills are many years above age. Most of those stories however, are "school stories" or children dealing with a variety of circumstances that would cause him to worry (divorce, homelessness, disabilities, etc.). It took some digging but we came up with books that have hard text and easier, sillier themes that appeal to the seven year old.

Sometimes, he reverts back to some "easier" books (both text and theme)- I'm fine with that as long as he is enjoying the book. I'm the same way, sometimes I want something difficult that makes me think, and sometimes I want formulaic "fluff" (usually as a "rest" after the the difficult book).

First grade has been the year that we saw a lot of mismatches. Thank goodness for this forum.