Assessment time limits shortened with concurrent extensions and specified search-triggered extension of assessment completion period. Amendments to section 153 shorten the prescribed completion period for certain assessments and substitute the time in subsection (1A) to align with the revised period, add cross-references to the new subsection (1A), and expand authority designations to include Principal Chief Commissioner or Chief Commissioner. A new subsection (3A) provides that where an assessment or reassessment is pending at the time a search under section 132 or requisition under section 132A occurs, and in cases involving seized or requisitioned valuables or books and documents, the period available for completion shall be extended by an additional defined duration. Explanation 1 is amended to include inventory valuation.