I switched the ceiling lights off in the very beginning [:(] There are two main lights, simulating my leds, which are just white light sources of a 40 cm in size, at 18% power, set at 220cm (the kitchen is 270cm high). Then there are two row of other lights:

• four 70cm white lights at 110cm, 9% power - to enlighten mid section
• four 50cm white lights at 30cm, 7% power - to enlighten bottom furniture and floor

So in essence no light touches the ceiling, it seems the renderer reduces the light's power very rapidly with the distance from the source. SH3D is 7.0.2 and I'm using simple phot-video rendering 2.4.1.
Here is my scene if anyone is kind enough to render for comparison:
Kitchen model