For a trip from TPE to 2 US east coast cities in early Feb, I found CX-AA flights are about 20+% more expensive than DL flights. The travel agent said the taxes (airport, fuel...) do not differ much, most differences come out from the ticket fares, especially the CX legs.

Is that a general situation? Or more on a case-by-case basis? I really like CX, but with a fixed travel budget and so many trips to make, this is really tough.