Relative residuals (data/model-1) against a common spline model applied to RGS, Resolve, and NuSTAR data (details in the text). Differences between residuals mainly indicate differences of the effective area with respect to the effective area calibrations. The residuals have been binned for clarity. The black and grey residuals refer to RGS1/2 below 3 keV and to FPMA/B above 3 keV.