Originally Posted by
pandaperth
Yes, I agree. Your ticket would only show LHR-SYD (SIN would not show) and so that can be changed to another through flight such as the QF one you showed, which stops in DXB but again DXB would not show on the ticket
Wouldn't work with this specific example. There are a few taxes that are collected even with transit in SIN on the same plane. These would have to be refunded (or collected) if you alternate between DXB/SIN transit point.
BA and QF YQ may also differ which would require potential reissue.
edit.
In saying that, I don't think $125 charge would apply under the spirit of the OWE rules. However, it will still require reissuance by the airline.