As far as your comparison to the Dominican republic, it is illogical. They are a sovereign nation, like Cuba, with a different currency. And besides, if an airplane is going from MIA-DFW or MIA-JFK you can't load it in SDQ, HAV, or anywhere else for that matter.
No its not. Those currecies could easily be broken down to a US equivelent(ok exchange rates vary) but for the purpose of comparing work vs compensation its perfectly logical.
The fact is thats costs vary, including labor costs even if the work is the same. Location, whether its a different state, city, county or country has a lot to do with it. Is what a FSC does in the Dominican Republic or Cuba any different than what a FSC does in DFW? Whats illogical is for the company to expect to pay the same for labor in New York as they would in Tulsa, and the only reason why they get away with it is the TWU.