Essays / Question on "additional infomation" on essay application [12]

I wouldn't put it... it sounds like you're making excuses.

Maybe try rewording it? Don't say "not up to par" etc

Well, of course, it will depend in part on what you have and have not covered already on the application. Anything you can tell the Committee about yourself that is relevant to what makes you a good candidate for their school will help you. For more information about what's important in a grad school admissions essay, have a look at this article: essayforum.com/graduate-4/admission-projects-beat-odds-165/