the four–parameter fit. The reduced $\chi^{2}$ decreases by 0.10 and 0.06 when changing from the six–parameter to the four–parameter fit for the low and high-stretch subsamples, respectively. That is, the four–parameter fit has a smaller reduced $\chi^{2}$ than the six–parameter fit (although only marginally smaller), and thus, the subsamples and the full sample are completely consistent with all having the same velocity for the red component.

argued that the difference in the red edge of the Ca H&K line profile was evidence that the subsamples have different ejecta velocities. But we have shown that simply varying the height of the redder Gaussian (and the bluer Gaussian) are sufficient to produce the red edge of the profile. That is, the apparent different in the red edge can be explained by different line strengths rather than different line velocities, and thus a difference in the red edge is not sufficient to distinguish different velocity features.

We also attempted to fix the parameters of the bluer Gaussian, but that did not result in good fits. From these tests, we see that (1) the red component does not necessarily have a different centroid (and thus velocity) for the two subsamples and (2) the blue 