Time limit for reassessment notices: extended limitation and exclusions protect procedural fairness in reassessment issuance. The rules set the time limit for issuing a reassessment notice and allow extended limitation where the assessing officer holds evidence-assets, event related expenditure, or book entries-indicating escaped income meeting the statutory threshold; separate notices may be issued for multiple affected years. Computation of limitation excludes time allowed for assessee responses and periods of judicial stay, and a short minimum extension is available to permit completion of statutory show cause proceedings when court orders would otherwise leave insufficient time. Late year search, authorisation or requisition events permit an additional short exclusion and deem certain notices issued on the terminal date.