Isle of Man Treasury has upgraded its online VAT return service to let businesses and agents correct errors in previously submitted VAT returns online, replacing the manual VAT 652 MAN error correction form in most cases. Returns can be amended for periods up to four years before the current date. Corrections must include a full and detailed explanation so the Customs and Immigration Division can process any additional tax due to or from the business, and supporting documents such as detailed VAT workings can also be uploaded. Some cases will still require a manual VAT 652 MAN submission. Newly submitted returns may not be available for amendment until system processing is complete, and amended return details may not appear immediately while validation checks are carried out. The Treasury also warned that penalties may apply if incorrect or misleading information is submitted.