My (Thai) wife went to the Min Buri tax office this (Friday, February 14th) morning. All of my documents were reviewed. The tax officer consulted with her supervisor, then told my wife that my Thai Tax Identification Number is now registered in their system as the same number that appears on my pink Thai ID card, that I don't need to file a tax return because my only income is my (U.S.) social security retirement benefits, and to just go home and don't worry about it.