S. 68 : Cash credits-Appellate Tribunal-Powers-Delay was condoned-Accountant inadvertently filed return declaring income u/s. 44AD and cash balance as at end of year-Onus upon department to disprove contention of assessee —No material brought on record to show cash generated by assessee from other activity subject to tax-Order bringing cash to tax as unexplained cash credit unsustainable.[S.44AD, 115BBE,253]