Slightly confused by some of this. Is there a good reason why, for example, you are flying SIN-BKK-SIN-CMB and buy an extra ticket rather than SIN-BKK-CMB which you could do without an extra ticket?

Also I assume that IST-YUL is via LHR? And ANC-SFO is via ORD or DFW?

It would be helpful to us here if you could list explicitly the DONE3 segments... Is it:

CMB-HKG-LHR-AUH-LHR-IST-LHR-YUL-DFW-ANC-SFO//LAX-SJU-JFK-HKG-SIN-BKK-CMB

In which case you have one more segment you could use in North America...