Simulated differential number counts in ALMA Band 6, retrieved with the corrected Bias and Superbias modes for four different central mask radii, divided by the underlying Input number counts. Shown here is the mean over ten run-throughs of the simulation (i.e. 580 realisations). The light shaded regions show the standard deviation due to cosmic variance; the dark shaded regions show the error on the mean (i.e. ). The errors are of approximately the same size for the Bias and Superbias modes, but for clarity they are only shown for the Bias mode.