I guess the $25 is telephone booking fee. AA charges the same too.

In light of the CX award seat availability, I would rather take the $0 change fee on AA than the $100 change fee on AS.

On our last trip to HKG we have changed our itinerary 3 times - started with MIA-DFW-NRT-HKG, to MIA-LAX-NRT-HKG to MIA-DFW-SFO-HKG - as award seats opened up for better itinerary, and we upfared from J to F on the last change when CX opened up loads of SFO-HKG F on the 747.

OP, dont forget you also can have stopover or open jaw on AS which is a r/t award.

With AA, it is one-way system so an open jaw is given if you want it. However you are also entitled to one stopover at North America gateway on each direction.

So you can literally do this on AA, same price, HKG-SFO (stopover) - YVR/ORD/JFK/YYZ or wherever you want to be in USA/Canada/Caribbeans/Mexico. On your way home you can start from anywhere in North America, fly to the CX gateway have a stopover and then fly back to HKG. In other words, you would have TWO trips in one price, to let you visit somewhere in North America other than SFO where you plan to go.