I am not sure what other legal routing, if any, exist when you purchase a United (016) ticket from LAX-MNL other then they allow you to go to HKG, keep in mind no more LAX-HKG non-stop only LAX-NRT/SFO-HKG and then HKG-MNL on CX/PR.

Just to let you know NW has flights to MNL via a one-stop NRT connection if you want to stick with a US based carrier.