As per case facts, the respondent company filed its income tax return claiming a deduction under Section 10A. After an initial assessment and rectification, the income was assessed as ‘Nil’. ... Subsequently, the revenue issued a notice to re-open the assessment, alleging that the Section 10A deduction was allowed in excess, leading to escaped income. The respondent's objections were rejected, prompting them to challenge the re-opening notice in the High Court, which sided with the respondent. The revenue then appealed to the Supreme Court. The question arose whether the re-opening of an already completed assessment was justified when based on a perceived excess deduction. Finally, the Supreme Court ruled that the re-assessment proceedings were merely a 'change of opinion' on facts already considered during the original assessment, particularly regarding the allocation of common expenses. It affirmed that Section 147 does not grant the Assessing Officer the power to review, but only to re-assess based on new, tangible material. Since the original assessment had already scrutinized the deduction, the High Court's decision to quash the re-opening notice was upheld, dismissing the appeal.