Hey @Sylvain_Mathieu 
Thanks for sharing the details here, really appreciate you taking the time and sharing your feedback.
This is still a known limitation right now, Delivery Customization Functions aren’t fully supported for subscription recurring order delivery groups. That said, we’re actively working on improving how subscriptions and delivery customizations interact, but I don’t have a specific timeline to share just yet.
In the meantime, one workaround that’s been working for other apps in a similar situation is to set up a dedicated delivery profile specifically for subscription selling plans. You can do this using the deliveryProfileCreate or deliveryProfileUpdate mutation with the sellingPlanGroupsToAssociate field, and set static rates on that profile. Since those rates wouldn’t be carrier-calculated, they wouldn’t be affected by the delivery customization function hiding them.
New carrierservice payload data
I know neither of these is a perfect solution, but they should help bridge the gap for now. I’ll update the thread here when there’s more to share on the longer-term fix. Let me know if you have any questions about either approach, or if they don’t work for you, I’m happy to pass your feedback along for sure so we get this logged.