If, for any period, an amount is paid as tax—

(a) Under chapter 21 or corresponding provisions of prior law by a person who is not liable for tax for such period under such chapter or prior law, but who is liable for tax for such period under chapter 22 or corresponding provisions of prior law, or

(b) Under chapter 22 or corresponding provisions of prior law by a person who is not liable for tax for such period under such chapter or prior law, but who is liable for tax for such period under chapter 21 or corresponding provisions of prior law,

the amount so paid shall be credited against the tax for which such person is liable and the balance, if any, shall be refunded. Each claim for refund or credit under this section shall be made on Form 843 and in accordance with §31.6402(a)-2 and the applicable provisions of section 6402(a) and the regulations thereunder in Part 301 of this chapter (Regulations on Procedure and Administration).