JC Double Taxed'

Once again, I have no need to become an expert of this topic.

Have the people that you consulted with reviewed the US-AS Totalization Agreement (there probably is one)., that might have alleviated your situation.

Did you EMPLOYER  pay AS pension to AS? If so, then YOIU did NOT. If the employer withhled it form yhour pay (and you also paid SS "tax"), then maybe the Totalization Agreement would have helped you.

Were you working for a US company in AS? 

In any case, your employer might make up for any tax ineffficiency.

Ignoring TAX for the moment, did yiou make money on your AS pension, which exceeded any tax inefficiency.

I really do not mean to gtry to resolve your tax problems, overall, for the many things I have pointed out, you were not double taxed, but MAY have paid a little more tax than if you worked in the US. I have given you things to check out. 

Bottom Line: If you are unhappy, then work in the US (or ask your Rep to enact fixes).