Comparison between the beam window function corrected BipoSH spectra obtained from WMAP maps (red errorbars), observed in V (top) and W (bottom) bands, and our detailed simulations of the respective channels (solid lines). The average BipoSH spectra across the DAs are denoted by the dashed lines. The saffron band shows the standard error derived from all the simulations for each band only (total 60 simulations for V and 120 for W), while the grey band also combines the error on the mask bias correction. Spectra from the simulated maps match the observed spectra very well, correctly reproducing the location of the peak and the zero crossings. Also plotted are the spectra (dash-dot lines) evaluated from the aPPS model parameterised by g₂₀ provided in Table 1 of Hanson et al. (2010) to emphasise that a surrogate estimator is unlikely to capture these subtle effects.