Median and median absolute deviation of the residuals (data/best-fit model) of the soft band cluster sample for XIS0 (black), XIS1 (red), and XIS3 (blue). The model is an absorbed single-temperature MEKAL, whose temperatures and metal abundances are forced to be equal in all instruments for a given cluster, fitted to 0.5–2.0 keV band using the effective areas modified with the contaminant model.