Providing your logistics partner Linnworks the IOSS number correctly ensures your shipments are handled appropriately.
You would need to ensure that the order item values passed to the shipping couriers for the IOSS shipments would be Tax exclusive.
Linnworks has introduced a new setting for our Shipping Integrations that allows determining whether or not Tax will be included in the unit cost submitted to the vendor for customs purposes.
This setting is available for all Shipping Integrations, however, not all integrations forward the customs information to the vendor. E.g. for most 3rd party integrations, only the Linnworks Customs Declaration is printed. Check the relevant Courier Integration documentation for available features.
This option is available in Linnworks.net > Shipping > Integrations > relevant integration line > Services > Edit > Customs Value Includes Tax.
Please note the setting only appears under international services and the section it is located under in available settings can vary depending on the integration.
When enabled (it is enabled by default) - Linnworks will submit the order Total Value and the Unit Value of each item with tax included.
When disabled - Linnworks will submit the order total and unit values with tax excluded.
The setting will apply to the data that is sent to the courier as well as to the printed values on the Commercial Invoice/CN22/CN23.