Reduction or waiver of interest: monetary limits fixed for tax authorities, subject to hardship, uncontrollable default and cooperation. The Board fixes tiered monetary thresholds allocating competence to specified income tax authorities to grant reduction or waiver of interest payable under the tax default provision: the lowest tier to Pr.CIT/CIT, intermediate to CCIT/DGIT, and highest to Pr.CCIT. Any exercise of these powers is conditional on genuine hardship to the taxpayer, default due to circumstances beyond the taxpayer's control, and the taxpayer's cooperation in relevant inquiries or recovery proceedings.