The p-value (vertical axis) of the cross correlation between the hard X-ray (7.2–12.0 keV) LC and the time derivative of the soft X-ray (0.4–2.0 keV) LC (Equation (1)) and the SNR (color scale) of the hard X-ray LC at various temporal binning choices. The strongest correlation is obtained with 6 ks bins, which is used in all other LCs in this Letter. Most choices of bin sizes between 4 and 8 ks yield a significant correlation with p-value <0.01 (including binning by the XRISM satellite orbit at 5747 s), and all have p-value <0.05. This indicates the observed Neupert effect is not an artifact of binning choice. In bins smaller than 4 ks the hard X-ray LC SNR drops below 20, making the correlation unreliable.