On the filing of the application, the commissioner shall determine the amount of refund to which the applicant is entitled. If the amount is not less than that claimed, the commissioner shall issue the refund from the tax refund fund under section 5703.052 of the Revised Code. If the amount is less than that claimed, the commissioner shall proceed in accordance with section 5703.70 of the Revised Code.
If the application for refund is for payment of an illegal or erroneous assessment, the commissioner shall include in the certified amount interest calculated at the rate per annum prescribed by section 5703.47 of the Revised Code from the date of overpayment to the date of the commissioner's certification.
R.C. § 5727.28