(1) Subject to this section, the amount of a credit to which a person is entitled by virtue of this Division is a debt due and payable to the person by the Commissioner on behalf of the Commonwealth.
(2) The Commissioner may apply the whole or a part of the credit in total or partial discharge of any liability to the Commonwealth of the person entitled to the credit arising under or by virtue of this Act or any other Act of which the Commissioner has the general administration.
(3) Where, under subsection (2), the Commissioner has applied an amount of a credit in discharge of a liability of a person to the Commonwealth, the person shall be deemed to have paid the amount so applied for the purpose for which, and at the time at which, it has been so applied.
(4) Where the amount, or the sum of the amounts, applied or paid by the Commissioner as a credit to which a person is entitled under this Division exceeds the amount of the credit to which the person is entitled, the Commissioner may recover the amount of the excess as if it were tax due and payable by the person.