This is a difficult question. Due to the fact that I don't know from which airport you start your travel and where are you travelling to it is a bit difficult to answer.

But let me try to:
+ If you are based at e. g. at a smaller airport without First/Gold lounge and make many short trips you won't really have many advantages because of a shared "Terraces" of similar combined silver/gold lounge.
+ We all don't know if you make your trip costing 550 USS only in a higher class than expected or make just a mileage run. In that case I am not really sure if it's worth.
+ Different if you always or often travel to the larger airports of Oneworld with separate lounges for silver and gold. Then this mileage run could be worth. But you should decide yourself.
+ There have been some larger threads about seat blocking policy on long-haul flights. Just read them carefully and this may enhance a better decision.

Maybe this helps...