Difference in the total stellar mass M_⋆ between PSS (out) and ESS (in) values as a function of model age t for a instantaneous burst SFH. Results adopting a base library without any AGN PL (npl), with a PL with the same index value as the input values (spl) and with PLs with α = 0.5, 1, 1.5, and 2 (mpl) are presented on top, middle, and bottom rows, respectively. Increasing AGN flux fractional contribution x_AGN at λ₀ = 4020 Å are represented from left- to right-hand side panels. Results from purely stellar models and models with PLs with α = 0.5, 1.0, 1.5, and 2.0 are represented by black, blue, green, yellow, and red lines, respectively.