Assessing Officer amendment powers permit targeted assessment amendments and recomputations upon specified triggering events and timelines. The provision empowers the Assessing Officer to amend completed assessments within specified time limits when defined triggering events occur, permitting targeted adjustments such as partner or member share corrections, recomputation of succeeding years for carried forward losses or depreciation, reassessment of transferor company capital gains, exclusion or allowance linked to reinvestment or foreign receipt conditions, allocation of foreign tax credit after dispute settlement, adjustment following revised consideration on appeal or reduction by authority, disallowance after patent revocation, and allocation of TDS credit; it also requires recomputation under the transfer pricing arm's length determination for two consecutive years within prescribed timelines.