Worked on the Hochfrequenz/BO4E-dotnet repository to enhance code consistency and maintainability by standardizing enumeration values for invoice items. Focused on refactoring the Rechnungsposition Zu-/Abschlag ENUMs, the work involved renaming and clarifying discount and surcharge names, particularly those related to electricity network charges, to reduce ambiguity and downstream mapping errors. Integrated Protocol Buffers to ensure that the updated enums aligned with API contracts and downstream consumers, improving compatibility and reducing integration issues. Utilized C# and protobuf to implement and validate these changes, addressing a key bug and contributing to a more robust and maintainable codebase.