400w Dimmable HPS Question?

Ive been using a 400w dimmable hps system (the ReVolt from gotham hydro)

and i was just wondering how many lumens does a 400w dimmable produce when dimmed?

400w/400w = 50,000 / 55,000

400w/300w = ???

400w/200w = ???

can anyone answer this? even if its with a ballpark number?

please and thanks!

This is pretty common sense, go ahead and use simple subtraction skills and take the amount of lumens produced at 400 watts of power and cut that in half and ta-da the amount of lumens being produced at 200 watts of power!

i guess i assumed it wouldnt be efficient while being dimmed to a lower wattage