Provisional assessment time-limits and submission rules govern enquiry, finalisation, extensions and recovery under customs procedure. Finalisation of provisional customs assessment prescribes that where duty is provisionally assessed for want of documents or information the proper officer must specify required items within fifteen days and the importer or exporter must furnish them within two months subject to recorded extensions; enquiries must be completed and transferred within a mandated period and the proper officer must finalise assessment within a prescribed timeframe after receipt of documents or conclusion of enquiry, with supervisory extensions and an overall outer limit; suspension applies where specified legal or appellate processes operate.