You're correct, Peter. The "post" will have the timestamp of when the "Draft" was started. It will post "up" in the thread when it first started. The only way to get it at the end of the thread is to do a 'copy-n-paste': copy the original Draft, delete the original Draft, start a new post and paste what you've copied into the new post, and then post it. The problem comes in when you've got images or photos in the post... they won't "paste"; once you've pasted the text of the original Draft into the new post, then you'll have to go back and re-insert the images/photos. (I know; I've had to just that once.)
But since we do know there is a potential post in the Draft stage, when we see the "NEW" icon in the thread we can always scroll up to see if the Draft has been posted yet, and then continue on from there. (And if the discussion continues on far enough, the Forum software will start Page 2, and then we'll have to page back to Page 1 to look for the original Draft.)
I hope this makes sense.
Dino.