NACs provide the most reliable measurement of mass-loss rate in the UV lines.*]{} Equally, we can picture that [*doublet*]{} SEI fits to stars in our sample would result in excellent fits to [*both*]{} NACs with a single set of unsaturated $\tau_{\rm {rad}}$ values. However in this case, when the doublet model matches the blue component at low velocity, the model will be too shallow (in this region) for the red component. This is the tell-tale signature of porosity affecting the lower wind velocity more severely than the near-$v_\infty$ NAC.

[lcccccc]{} & & & & & &

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HD 13866 & 860 & 0.06 & 3.0 & 0.88 $-$ 0.95 & 1.92 $\pm$ 0.40 & 1.07 $\pm$ 0.61\
HD 47240 & 970 & 0.12 & 3.0 & 0.85 $-$ 0.98 & 1.75 $\pm$ 0.39 & 1.17 $\pm$ 0.36\
HD 111990 & 715 & 0.12 & 3.0 & 0.80 $-$ 0.85 & 1.74 $\pm$ 0.20 & 1.12 $\pm$ 0.19\
HD 51309 & 730 & 0.09 & 0.5 & 0.88 $-$ 0.98 & 1.70 $\pm$ 0.86 & 1.34 $\pm$ 0.60\
HD 36371 & 465 & 0.16 & 3.0 & 0.75 $-$ 0.85 & 1.83 $\pm$ 0.53 & 1.41 $\pm$ 0.72\
AV 264 