EEL or PFC info

[dolphinsd]

With other providers we use EEL or PFC codes for customs.

We do not see this field on your c# library.

EEL or PFC:When shipping outside the US, you need to provide either an Exemption and Exclusion Legend (EEL) code or a Proof of Filing Citation (PFC). Which you need is based on the value of the goods being shipped.
If the value of the goods is less than $2,500, then you pass the following EEL code: "NOEEI 30.37(a)"
If the value of the goods is greater than $2,500, you need to get an Automated Export System (AES) Internal Transaction Number (ITN) for your shipment. ITN will look like “AES X20120502123456”. To get an ITN, go to the AESDirect website.
An ITN is required for any international shipment valued over $2,500 and/or requires an export license unless exemptions apply.

from https://omnibasis.freshdesk.com/support/solutions/articles/36000206009-package-customs-information