Voluntary revision of entry after clearance allows self-assessment, voluntary duty payment, and refund treatment on excess duty. Voluntary revision of an entry after clearance is permitted for an importer or exporter, subject to prescribed form, manner, time and conditions. On revision, the importer or exporter must self-assess the duty, and any short-levy, non-levy, short-payment or non-payment may be paid voluntarily with interest. Where the revised entry shows excess duty payment or a full refund is required, the revised entry is treated as a refund claim under section 27. The proper officer may verify revised entries and re-assess duty where self-assessment is not correct.