Ohio Rev. Code § 5715.28: Decisions by department of taxation shall be binding.

The tax commissioner shall decide all questions that arise as to the construction of any statute affecting the assessment, levy, or collection of real property taxes, in accordance with the advice and opinion of the attorney general. Such opinion and the rules, orders, and instructions of the commissioner prescribed and issued in conformity therewith shall be binding upon all officers, who shall observe such rules and obey such orders and instructions, unless the same are reversed, annulled, or modified by a court of competent jurisdiction.