Income tax payments received by the Comptroller shall be applied as follows: Payments accompanying returns shall be applied to the period covered by the return in the following manner: First to any penalty; Second to accrued interest; and Third to the unpaid tax. All other payments shall be applied to the earliest delinquent tax year in the following manner: First to any penalty; Second to accrued interest; and Third to the unpaid tax. A refund of income tax due a taxpayer shall be applied first as provided for in §A(2) of this regulation, and then in the following order of priority: To any debt collection intercept under COMAR 03.04.05 or 03.04.06; and To the taxpayer of any remaining balance.