Stability of the {Ω_m, σ₈} Fisher ellipses when varying the number of cosmologies around the fiducial value, N_cosmo, or the weighting scale, σ; specified through the Pearson correlation coefficient p, measure of the orientation of the ellipse, and the Figure of Merit FoM, measure of the area of the ellipse. The different colors correspond to the given combination of order for the aperture statistics considered in the analysis. Comparison of the results when marginalizing over h and w₀ in the computation of the ellipses (Left), with stable ellipses; and the results when we try to constrain all cosmological parameters from cS19 (Right), where projection effects from the unconstrained parameters make the ellipses unstable.