Interpolation errors presented as a function of τ_scaled (bottom x-axis) and ρ_c (top x-axis) that resulted from interpolation along the evolutionary track with M = 1.245 M_⊙ for all ℓ = 0 frequency modes, with radial orders n ∈ [9, 23] indicated by different colours. Each subplot presents the results for a different interpolation method, considering different methods – linear (top panels) or cubic splines (bottom panels) – and different age proxies – τ_scaled (left) and ρ_c (right).