Lighting Switches?

[Magic]

High family this might be a dumb question but I noticed when I got my GN light there are two switches, one turns on the outside for lights and one turns on the middle two. Can anyone tell me what this is for and is there an effective way to use this feature?

 

[TaNg]

Is simply so you can use less light in the early stages the idea is 2 spots for seedlings, 4 spots for veg and 6 spots for flower.

 

[Magic]

nice thanks tang. would it be a bad idea to leave the 2or4 spot on instead of having a dark time? pretty much giving them more light during the day (full lighting with cfls) and less at night(2 or 4 spots on led)?