Why two bi-xenon per assembly?

On the hidforum.com a poster mentioned being very disappointed with the hella de xenons. Claimed the beam pattern was very poor and that glare was pretty bad, he claimed that the de halogens were much better in both departments.

Also on hidforum.com there was discussion of a ballast that runs at 35W and 50W, you could even switch while it was in use. Maybe that could be used at 50W to drive two lamps.