The Muslim civilians would likely include men right? It doesn't say it was only women and children who were allowed to leave if they paid. The details on those missing from Srebrenica show some were last seen around Srebrenica a year or more it was taken over, so probably many had left Srebrenica and weren't even there in July 1995. The civilians who bribed their way out to get to Tuzla could have then traveled elsewhere in Bosnia or left it altogether.
Sorry, I forgot to post the source:
http://www.hri.org/news/balkans/yds/95-11-23.yds.html (<- Click)
Karadjordje