Comparison of 3D Lyα forest power spectrum ratios, P_mock(k)/P_ref(k), between the predicted and reference power spectra at different redshifts. Results at z = 1.8 (dotted purple line) and z = 2.2 (dashed green line) are obtained via independent calibrations. Instead, the z = 2 result (dash-dotted blue line) corresponds to the Lyα forest power spectrum that we get by applying the nonlocal FGPA model with parameters linearly interpolated at z = 2 from calibrations at z = 1.8 and z = 2.2. The gray shaded areas stand for 1%,2%,5%, and 10% deviations, from darker to lighter.