Chrisbaktis - I'll be releasing an update today, and that will be included as an admincp option.
Areku - Admin's override all restrictions, for various reasons, that's why you can leave multiple feedback within the restricted timeframe. If a postid is submitted in the URL all it does is back-check to the the threadid, it's just there for convience. I allowed duplicate threadid's because on many sites a person has a single "FS" listing URL, thus multiple people could end up linking to it. Like I said, a person is free to edit this however they feel fit for their own forum use. Everyone runs their forum differently, for instance, in my FS/WTB sections, a user can create the thread and edit it, but that's it. People can not reply because that would alter the natural order of items being listed FS.
zlos - I'll be sure to fix that with the next update.