∇_s as a function of log₁₀ (ρ), comparing the outputted values and those reproduced using Equation (7) (plus markers), for a selection of 0.3 M_⊙, (a) 10 Myr or (b) 1 Gyr stellar models at α_MLT = 0.8–1.7 (Δ0.3). α_MLT = 1.7 is chosen to be the “unperturbed” model. As α_MLT decreases, the 10 Myr model’s reproduced ∇_s increasingly diverges right at the photosphere, due to the non-negligible low efficiency regime.