Fit parameter degeneracy for the 1, 3, and 5σ levels of each instrument in different energy bands. The green contours (circles) refer to the soft vs hard band. Equality of temperatures for two bands is given for a = 1 and b = 0. The deviation in σ from equality is given in the legend, as well as the expectations (blue pentagon, black square, and red diamond) for a multitemperature ICM with the parameters (temperature, emission measure ratio) of the cold component given.