Originally Posted by
fastair
Yes, there are. "Stitching" a group of local inventories is not the same as a origin-destination inventory being available. Unless you want to pay individualy for each flight, instead of getting a singly priced fare from A to B thru as many C,D,E,F of your choosing, your method most likely is not necessarily going to return the ticket you want. Carrier A may want to sell a local Q fare from A to B and also a local Q fare from B to C. That doesn't mean that they want to sell a Q fare from A to C via B, as they can may be able to make more $$ selling the separate tickets. If you want from A to C, that fare must be available when requesting space from A to C, not from A to B and a separate request from B to C.
Because you find "local" inventory in the class you want on multiple individual legs, does not make it "phantom" if not there when requesting it for a set of connecting flights, it only means that inventory is there on the legs for the single segment price on each leg, but may (or may not) be there for a single price for the combined legs when booked as a connection.
Married segments do not change award ticket pricing and however UA has programmed the fare calculation system, published routings are not taken into consideration. The poster can certainly piece together the itinerary he mentions above and it should price correctly.
UA's search engine is not strong enough to come up with that routing even though is is a perfectly valid one for award ticket purposes.