Provisional assessment extended to export consignments with prescribed timelines for submission and finalisation of assessments. Amendment expands provisional assessment under section 18 to cover export consignments and inserts that where documents or information are required after provisional assessment, the importer or exporter must submit them within prescribed time and the proper officer shall finalise the provisional assessment within such prescribed time and manner; it also substitutes the reference to section '28AB' with '28AA' retrospectively from the eighth day of April, 2011.