Marginalised one-sigma constraints by varying the number of simulations to compute the derivatives (top panel). Bottom panel shows the relative improvement of over ⟨w₁₂|r₁₂⟩_p. The parameters in consideration are the six cosmological parameters and one nuisance parameter (b) as shown in the legend. The grey horizontal band denotes the region where the variation in the constraints are within 5% compared to the constraint obtained using N_deriv = 500.