Variation of the matter power spectrum boost (15) at z = 0 as each cosmological parameter is varied away from its fiducial value in Table 2 (equivalent to the transformation in Fig. 5a). The bottom right plot is special; showing the ratio of the nonlinear boost from FML/COLA to the linear boost from HI_CLASS for all boosts in the 7 other plots at more redshifts z = 0.0, 1.5, 3.0. It shows that B ≈ B_lin to 1% for k ≤ 1 h/Mpc, and 2% for k ≤ 5 h/Mpc.