$\delta \eta \equiv \mathrm{Log}(M_{500}^M/M_{500}^{\mathrm{SZ}})$ as a function of the redshift. The error bars indicate the 68% statistical uncertainties. Points are colour-coded according to the values of the A² coefficient. The red vertical line indicates the pivot redshift z = 0.2. Note that we have included the four outliers (δη > 0.8) as well as the full double systems PSZ2G040.03+74.95 and PSZ2G218.81+35.51 to highlight the values of A².