Back on ASPD they had a feature turned on that would include a tag line of "
last edited by" with a time stamp if you did an edit.
IF you edited it within 5 minutes no tag was inserted.
If you edited it between 5 minutes and 1 second and the allowed edit time meaning under 59 minutes and 59 seconds then the
last edited by string would appear.
Check the time between when you post and edit. I know that is how it worked back on ASPD because I tested it to find when the tag would appear.
Here is a thread about that option.
http://www.vbulletin.org/forum/showthread.php?t=180375
In my opinion, it would probably cause more grief for the staff doing edits if only 1 or 2 staff were always shown as editing.
I recall St Chris posting something about the editing of posts or removal of posts should not happen often but if needed most times you see a edited by staff tag inserted.