Tenn. Code Ann. § 67-1-1008

If the back assessment or reassessment is sustained, the cost of the proceeding shall be added to the taxes and collectible as such. If the back assessment or reassessment is set aside, the cost shall be paid by the jurisdiction to which the taxes would have been payable, or by the complainant if the board determines the complaint was filed or prosecuted by the complainant without good cause. In a case of connivance, fraud, deception, misrepresentation, or failure to file a personal property schedule, the board may impose a penalty not to exceed fifteen percent (15%) of the taxes due, which shall be added to the taxes due and be collectible as such.