The ratio ℛ of normalized variance at the observer inclination angle θ_o = 81.6° with respect to the case θ_o = 30°. The dependence on the dimensionless Kerr black hole parameter a is plotted for the assumed emissivity profile β = 3.5, for three values of the flare lifetime scale t₀, as indicated in the plot. Three horizontal lines give the enhancement ratio ℛ for NGC 4258 given in Eq. (10) (middle line), and the range of errors (upper and lower lines). The simulated light curves were longer by factor 8 compared to those used in Figs. 1, 2.