D'oh, you are correct! I'm not sure about the Dimlux fixture though. The site says to use it in a 1000w high-frequency ballast that's dimmed down to 600w.
The Dimlux (if it's the one I am thinking of is a 630w fixture, but it's really 2x315w: http://www.dimluxlighting.com/dimlux-630-cmh.html
I...