Difference in J_max (top panel) and H_max (bottom panel) between the NIR S/N simulations (Sect. 5.3) and reference sample as a function of S/N. The binned median and standard deviations are shown as red squares with error bars. Simulations with all S/N values are shown in here. The average S/N of CSP SNe Ia at z > 0.08 are shown as vertical lines (21 and 8 for J and H bands, respectively); N is the total number of simulations.