(a) The term “overpayment” includes:

(1) Any payment of any internal revenue tax which is assessed or collected after the expiration of the period of limitation applicable thereto.

(2) Any amount allowable for a taxable year as credits under sections 31 (relating to tax withheld on wages), 39 (relating to certain uses of gasoline, special fuels, and, lubricating oil), 43 (relating to earned income credit), and 667(b) (relating to taxes paid by certain trusts) which exceeds the tax imposed by subtitle A of the Code (reduced by the credits allowable under subpart A of part IV of subchapter A of chapter 1 of the Code, other than the credits allowable under sections 31, 39, and 43) for such year.

(b) An amount paid as tax shall not be considered not to constitute an overpayment solely by reason of the fact that there was no tax liability in respect of which such amount was paid.