(1) When a State makes a deduction from a taxable amount under section 9 (or purportedly under section 9), the taxpayer is entitled to a credit equal to the amount deducted.
(2) However, the taxpayer is not entitled to a credit for any amount purportedly deducted under section 9 in relation to an amount paid under a valid State franchise law.
(3) The credit is a debt due to the taxpayer by the Commissioner on behalf of the Commonwealth.
(4) The Commissioner may apply some or all of the credit against the taxpayer's liability to windfall tax (whether or not that liability is in respect of the taxable amount that gives rise to the credit). The Commissioner must refund any amount not applied.