I haven't really touched HLOD stuff since it came out, so things may have changed since. However with Plaza specifically, doing the HLOD process actually just crashes the editor after some time. I was looking forward to using it as Plaza is definitely one of the harder maps to optimise.
We've LOD'd a lot of models now anyway, and using instancing quite often throughout.. at least in some more of the recent maps. Waterhole, Altitude and Midori however DO use HLOD currently.