UMich Expression of Continued Interest

Hi all, I recently got deferred from the University of Michigan. They’re asking for an “expression of continued interest”, but I’m a bit confused on what to write about. Would it be similar to a Letter of CI where I list out my recent achievements or would it be like another “Why U Mich” essay, where I reassure them that they’re my number one choice and how they’re a great fit for me? Since it’s only 250 words, I’m guessing I shouldn’t include any formalities like “thank you for considering me” and instead get straight to the point.
Any comments/advice would be greatly appreciated, thanks!