additional document??

<p>Recently, I told my counselor that I was a little disappointed in my grades sophomore and junior year because I took too many AP's and didn't do as well. She suggested that, if I wanted, I could write a short additional document explaining it. </p>

<p>I'm applying to some pretty competitive schools (but WashU first choice) so I was wondering if this is a smart move... Will they get the wrong idea? Is it worth explaining at all?</p>