Article 148 empowers the Tax Authority to correct its own work. The Authority must rectify or revise an existing assessment, or issue an additional assessment, if the original was found to contain an error, omission, or was inadequate in its scope. This power applies to both formal assessments issued by the Authority and 'deemed assessments' under Article 143 bis. However, these revisions are subject to the outcome of any final judicial decisions on the same tax year. This ensures that the tax bill accurately reflects the true liability discovered upon further review or new information.