No addition u/s 68 can be made in respect of sale proceeds already offered as income:

Once the sale proceeds have been offered as income by the assessee and the same has been accepted by AO, no addition in respect of the same can be justified u/s 68 or else, it shall tantamount to double taxation of the same income.

[VISHAL EXPORTS OVERSEAS LTD. - TAX APPEAL No.2471 with 2473, 2475 & 2476 of 2009 - GHC]