So out of curiosity, a sample scenario:
If I were to make a booking on United.com (for the 016/PQDs), say, FRA-SIN on LH then SIN-FRA on SQ, would that become a single United 016 number or two? Different directions, different operating carriers/not codeshare flight numbers?
What about an open-jaw? Say, if I went FRA-SIN LH then SIN-LHR SQ?