  Radiative feedback from luminous, massive stars during their formation is a
key process in moderating accretion onto the stellar object. In the prior
papers in this series, we showed that one form such feedback takes is UV
line-driven disc ablation. Extending on this study, we now constrain the
strength of this effect in the parameter range of star and disc properties
appropriate to forming massive stars. Simulations show that ablation rate
depends strongly on stellar parameters, but that this dependence can be
parameterized as a nearly constant, fixed enhancement over the wind mass loss
rate, allowing us to predict the rate of disc ablation for massive (proto)stars
as a function of stellar mass and metallicity. By comparing this to predicted
accretion rates, we conclude that ablation is a strong feedback effect for very
massive (proto)stars which should be considered in future studies of massive
star formation.
