Quick question about grow lights with dimmable ballast

[Graff420]

Alright im running a 600watt dimmable/digital ballast with a 600watt MH bulb but im running it at 250watt and going to move it up to 400 for the flowering.
Now my question is should i keep my lights at the hight for 250w or 600w not sure so iv been keeping my like about 12.5 inchs away

 

[POKEDSMOT]

Watts are watts. If you are using 400w then it should be the distance for a 400w.

 

[Graff420]

Iight thanks just wanted to make sure so i dont mess her up but thanks