The Arkansas Public Service Commission shall have the full power and authority in the administration of the tax laws of this state to have and exercise general and complete supervision and control over:
(1) The valuation, assessment, and equalization of all property, privileges, and franchises; and
(2) The several county assessors, county equalization boards, and other officers charged with the assessment or equalization of property taxes throughout the state, to the end that all assessments on property, privileges, and franchises in this state shall be made in relative proportion to the just and true value of the property, privileges, and franchises, in substantial compliance with the law.