Comparison between the envelope binding energies E_bind of selected stellar models computed with the default assumptions (black line) and in four model variations with increased spacial or temporal resolution (see text for details), plotted as a function of the stellar radius. Selected stellar masses are 12, 16, 20, 25, 32.5, 40, 47.5, 55, 65, and 80 M_⊙. Each panel shows a different metallicity. Diamonds mark the onset of core-helium burning, crosses indicate central helium depletion. Shaded regions mark the area of uncertainty span by model variations, with interchanging colors to increase readability. We note that only the post-MS evolution is included in the figure. Differences between the models are likely mainly due to envelope inflation and density inversions in the outer envelopes; see text for details. None of the numerical difficulties affect the conclusions of this study.