Texas Tax Code - TAX § 154.308. Deficiency Determination, Penalties, and Interest

(a) If the comptroller has reasonable cause to believe that a tax report or the amount of tax paid is inaccurate, the comptroller may compute and determine the amount of tax, penalty, and interest to be paid from information contained in the report or from any other information available to the comptroller.

(b) On making a deficiency determination, the comptroller shall notify the person by mail or personal service. Service by mail is complete when the notice is deposited with the U.S. Postal Service.