I feel as though any topic that has been paid for in fg should be able to be edited for more than the 10 minutes it's allowed. I think a week is appropriate so things can be fixed (especially guides) or trade lists with paid topics can be updated after some stuff was sold.

you have 30 (and not 10) minutes to edit your post

without the edit limit scamming would be much easier.
post thread, wait for some1 to reply, scam him, edit thread.