Section 61. Credit and debit notes
Subject to the provisions of sections 8 and 60, where a tax invoice has been provided as contemplated in sub-section (1) of section 60, and-
(a) the amount shown as tax charged in the tax invoice exceeds the actual tax charged in respect of the sale concerned, the seller shall provide within such period as may be prescribed, the purchaser with a credit note of the sales of goods involved in the transaction, containing such particulars as may be prescribed;
(b) the actual tax charged in respect of the sale concerned exceeds the tax shown in the tax invoice as charged, the seller shall provide the purchaser with a debit note, containing such particulars as may be prescribed:
Provided that not more than one credit note or, as a case may be, debit note shall be issued for the amount in excess.