The optional essay is not a personal statement. If you decide to complete the optional essay, it is an essay that should accompany everything else you've already written and not be repetitive in any way. Ideally, it will address something extraordinary you would like to further elaborate on or something negative you would like to explain to the admissions committee. When I was a member of an MBA admissions committee, my colleagues and I would have much rather seen an explanation (not an excuse) for low grades that first semester of college or the employment gap the applicant had last year. Otherwise, we would have probably come to some crazy conclusions on our own. I often refer to the optional essay as "The Elephant in the Room Essay" because it is an ideal place to explain a glaring weakness that could be held against you, but when explained allows the admissions directors to see you in a different light. I wish you all the best.

Sincerely,
Mary Pat Jacobs
Director, Apply Point Admissions Consulting
www.applypoint.net