I guess no anecdotal evidence so far? It was what I was looking for by asking the question. I have successfully done date changes with both BA and AA ticketed itineraries without repricing and before the the start of travel. (Thanks to this thread and my own experience I quickly refunded QF ticket). I also eliminated DXB stopover recently, and I am not sure now it would be possible to insert that stopover back. Will keep everybody posted in case I try and do that, even though the risk to mess up pricing as well as my current travel needs make it unlikely I'd seek those changes.