IV.T204 — Window Depth–Loop Order Correspondence

Window sequence W₃(3)=17, W₄(3)=18, W₅(3)=19 provides loop-order coefficients. NLO: W₃(4)=5 (sin²θ_W NLO). NNLO: W₄(3)=18 (sin²θ_W NNLO). Inflationary: W₅(3)=19 (δ_h=ι_τ/19).