The Δχ² frequency distributions of the flat-sky (green) and Limber (purple) approximations compared to the full result, with the spread provided by the Gaussian covariance for each survey configuration. The DR1 bin configuration is shown in lighter colours, while the eventual DR3 bin result is shown in darker colours. The improvement of the flat-sky over the Limber approximation is seen in the closer proximity of the former’s distribution to the dotted vertical black line at Δχ² = 0, most notable in the DR3 bin case. The histograms are each normalised to their own peak values and the x-axis is log-scaled above Δχ² = 50.