If I flag a question on SU, I have the three close reasons (product reccomendations, software dev, web apps, the "This question belongs on another site" or "Other (add a comment).

If I flag a question on SF, I have the three close reasons, and "this questions belongs on another site" but no "other - add a comment" dialogue.

This happens in both IE 9 and FF 21. I have 2233 rep on SF and 4616 rep on SU.