During December 2025, Killian Davies developed fee management capabilities for DEFRA’s epr-payment-service and epr-payment-facade repositories, focusing on accurate 2026 registration fee handling and flexible compliance calculations. He implemented new registration fee logic using C# and Entity Framework, introducing EF Core migrations and DateTimeKind adjustments to support precise financial operations. Killian added an IncludeRegistrationFee flag to the ComplianceSchemeFeesRequestDto API, enabling conditional fee inclusion based on user input. His backend development work improved pricing accuracy and reduced the risk of incorrect charges, demonstrating depth in database migrations, API design, and unit testing while addressing cross-repository impacts for end-to-end fee management.