Can carriers or qualified parties mix duty methodologies for international mail shipments?

Can carriers or qualified parties mix duty methodologies for international mail shipments?

No. As of August 29, 2025, and until February 28, 2026, carriers or other qualified parties must apply the same duty collection methodology to all postal shipments throughout a duty remittance period. The duty collection methodology may be changed once per calendar month, providing at least 24 hours of notice to CBP. Effective February 28, 2026, only the ad valorem duty methodology may be used.