Impact of changing the fit phase range from ϕ  ∈  [−10, +40] d (ref) to ϕ  ∈  [−5, +30] d (comp) on the estimate of the SALT2 light-curve parameters x₁ (top), c (middle), and observed Hubble residuals, derived from x₀ assuming a default cosmology (bottom). The x-axis in each panel shows the reference parameter (e.g., c_ref), and the y-axis shows the difference (Δ c ≡ c_ref − c_comp). In each panel, the horizontal gray lines show the median parameter error, and the marker color indicates the significance of the deviation from zero. The right ticks in the stretch and color panels show the corresponding magnitude impact, assuming α = −0.15 and β = 3.15.