Penalty limitation for minor tax breaches protects rectifiable documentation errors; procedural safeguards and mitigation on voluntary disclosure. No penalty shall be imposed for minor breaches-including easily rectifiable documentation errors made without fraud or gross negligence-and penalties must be commensurate with the breach. Authorities must provide an opportunity to be heard, state the nature of the breach and the legal provision relied upon, and may mitigate penalty for prior voluntary disclosure. The section excludes cases where penalties are fixed sums or fixed percentages.