Correction factor F_N II (= ) as it follows from various radiation-hydrodynamic model sequences, plotted over stellar absolute magnitude, M_V. Evolution is always from left to right. The abscissa is broken at M_V = 5, and the faint part is expanded to provide more clarity. As compared to Fig. 5, three additional sequences were included. The dots along the velocity sequences correspond to time steps of 10³ years each and are meant only to illustrate the pace of evolution, not absolute post-AGB ages. The 0.595 M_⊙ sequence with α = 3 reaches very early a maximum F_N II(= Ṙ_out/V_[N ii]) of 7.5. The inset illustrates the time evolution of F_N II during the nebular recombination phase (0.625 and 0.696 M_⊙ only) when F_N II becomes smaller than unity and even negative for a very brief time span. Note that for the earliest evolutionary stages, M_V ≤ −1, our predictions can be uncertain because of the extremely small sizes of the model nebulae.