Post-export conversion of shipping bills allowed under instrument-based schemes with procedural limits and conditional approval. Post-export conversion of shipping bills to an instrument based scheme is permitted subject to a time-limited written application, discretions for jurisdictional Commissioners to extend filing periods, and payment of prescribed fees. Conversion is allowed only where all conditions of the target instrument based scheme are met, the exporter has not already availed benefit of the originating scheme, customs automated system presentation requirements are complied with, no contraventions or investigations are pending in respect of the export, and documentary evidence existing at the time of export supports the conversion.