I would turn down your diffuse_value to something other than 100%.  Try 85 or lower.  Definitely lower your light intensity; with Gc lighting can be set to a lesser value. 

Now, exactly, what are you trying to achieve?  Since it is an interior you are trying to light balance, I would recommend striving for some realistic light placements with point or spot lights.  Especially with inverse square attenuation to give you a light fall-off affect.