Reference to Principal Commissioner for declaring arrangements as impermissible tax avoidance and determining consequential application. Assessing Officers may refer pending assessments to the Principal Commissioner or Commissioner to seek declaration of an arrangement as an impermissible avoidance arrangement and its consequences under Chapter XI. The Principal Commissioner or Commissioner may issue a notice, allow hearing, direct declaration if no objections are filed, or refer contested matters to an Approving Panel. The Approving Panel may declare arrangements impermissible, specify applicable tax years, order further inquiries, and issue binding directions from which no appeal lies.