The Commissioner sought to revise the assessment on the ground that the assessment order made no reference to depreciation; however, omission of a reference does not automatically establish that an error was committed. The Tribunal had previously decided the identical issue for related assessment years and those findings had subsequently assumed finality. Since the Tribunal’s prior order on identical facts was available and relevant, and because no consequential assessment under section 153(3) had been passed within the statutory period, the revision order was untenable and barred by limitation. The appeal was allowed.(AY.1995-96)