TP protested the manner in which the Department calculated interest on an assessment of corporation income tax. TP’s original income tax returns showed overpayments of tax for the three tax years for which deficiencies were later assessed. TP’s original returns had requested that the overpayments be credited to the next year’s liability and TP applied the overpayments to its estimated quarterly tax payments for the following tax year. TP requested that the overpayments be applied to offset its assessed underpayments for calculation of interest without regard to the fact that the overpayments had already been applied in accordance with TP’s instructions. Protest denied.