Comparison of the stable mass-transfer phase of a binary system calculated with the settings of the original article (marked ‘CWL’) and a truly conservative calculation. The initial conditions are identical: an initially 4 M_⊙ donor star with a radius equal to 12.7 R_⊙ loses mass to an initially 1.2 M_⊙ point-mass companion. In the top panel, the solid lines show the mass-transfer rate, whilst the dotted lines show the orbital period, corresponding to the right vertical axis.