Article 161 bis provides the procedural bridge between an objection decision and the final tax bill. Once a decision on an objection is issued (whether confirming, reducing, or modifying the initial assessment), the Tax Authority is required to make the necessary formal assessment to execute that decision. This ensures that the official tax record and the taxpayer's account are updated to reflect the outcome of the objection process, providing a final, legally enforceable figure for the tax year in question based on the administrative review.