Assessee entered into Memorandum of Understanding (MoU) with sister concern N.K. Proteins Ltd. (NKPL), a Star Trading Export House, for export of FSG Oil. Due to quality differences, NKPL realized lower export prices than prices invoiced by assessee. NKPL raised debit notes for price shortfall, which assessee accounted as adjustment against sales and claimed as business expenditure under section 37(1). Assessing Officer disallowed debit note amount treating it as non-genuine. Commissioner (Appeals) confirmed disallowance. On further appeal, Tribunal concluded that debit notes issued for price differences between assessee and sister concern NKPL were valid, as NKPL had already offered the corresponding amount to tax. High Court held   that in view of fact that amount was already charged to tax in hands of NKPL, same was rightly not added again in hands of assessee by Tribunal and therefore, there was no infirmity in findings arrived at by Tribunal. SLP of revenue was dismissed  since there was an inordinate delay of 392 days in filing SLP and also on merits. (AY. 2012-13)