Thai Tax Return

I've been browsing the Thai Revenue Department's web site, and I can't seem to get an answer to a specific question: Do I need to file a Thai Tax Return even if my income is subject to a tax agreement with another country?

In my case, that other country is the U.S. It appears my income (pension) is exempt from Thai Income tax as defined in the tax agreement:

"Subject to the provisions of paragraph 2 of Article 21 (Government Service), pensions and other similar remuneration paid to a resident of a Contracting State in consideration of past employment shall be taxable only in that State."

While I DO have interest income from a savings account in Thailand, the Bank withholds the tax on the interest. The amount withheld is so small that it is not worth the effort of filing a tax return just to recoup that amount.