  In gravitational lensing, steeper mass profiles generically produce longer
time delays but smaller magnifications, without necessarily changing the image
positions or magnification ratios between different images. This is well known.
We find in this paper, however, that even if steepness is fixed, time delays
can still have significant model dependence, which we attribute to shape
modeling degeneracies. This conclusion follows from numerical experiments with
models of 35 galaxy lenses. We suggest that varying and twisting ellipticities,
features that are explored by pixelated lens models but not so far by
parametric models, have an important effect on time delays.
