Originally Posted by
toasttemp
As Chrus posted earlier, heroic lockouts are still bound by raid ID, whereas a normal lockout 'binds' what bosses you have killed. So once a boss is killed once in a raid ID, it is gone from that raid ID and subsequent sharing of that raid ID. Not a problem for ICC/Invincible farming, since you can switch to heroic after accepting a normal save, but it doesn't work for newer raids that require all earlier bosses to be killed on heroic.
Incidentally, you can speed up the group forming process and a couple of log-ins/log-outs by selecting 'auto-accept' once you have created your listing. You may get some random realm-hoppers join your group, but once lead is passed to you (since the leader has DCed) you can disable auto-accept and toss out those uninvited guests if they haven't already left.