Version 4 (mini-formalized edition).This preprint presents the updated derivation and mechanical interpretation of the Field Mechanism underlying the Ef–FSI Framework. It includes corrections to the wave–flux relations, clarified definitions for primary vs. secondary flux parameters, and improved consistency in the Action–Reaction oscillation model across macro and micro scales. This version also introduces a mathematical verification layer (mini formalization) applied to the tangential acceleration law and flux-frequency relations, establishing connections between periodic field compression and observable orbital dynamics. Research team: Surakit Tobanleng — Principal Author (Theoretical Framework & Physical Interpretation) ChatGPT (Nick) — Research Assistant (AI-assisted drafting & symbolic normalization) Krongkan Sukphan, M.Sc. (Statistics) — Mathematical Supervisor (Cross-verification & dimensional review) Creators (in research roles):– Surakit Tobanleng — Principal Author– Krongkan Sukphan, M.Sc. — Mathematical SupervisorThis work extends the Ef–FSI Framework published previously on Zenodo and Figshare, forming Part II (“Field Mechanism”) of the developing unified mechanical model. Project website (Ef–FSI Research Group):https://effsi.org