The state tax commission shall prescribe the forms of all certificates, blanks and books required under the provisions of this law and shall, with the advice of the attorney general, decide all questions that arise in reference to the true construction or interpretation of this law, or any part thereof, with reference to the powers and duties of county or township tax officers, and the decision shall have force and effect until modified or annulled by the judgment or decree of a court of competent jurisdiction.

(RSMo 1939 § 11164, A.L. 1959 H.B. 106)