Cumulative distribution of the ΔC statistic derived from 1500 Monte Carlo simulations, assuming Model I (see Table 2) as the null hypothesis. Synthetic XRISM/Resolve spectra were generated matching the exposure time of the real observation. For each simulation, ΔC is defined as the difference in the C-statistic between the best fits obtained modeling the simulated datasets with Model I and Model n8 in Table 2. The vertical green line indicates the mean simulated ΔC, while the red line marks the 3σ confidence threshold. The purple line represents the ΔC value observed in the real data.