I recall seeing in a Digital Tutors video that scaling V-ray rect lights would mess the brightness up, and to change the size from within the light attributes instead. I believe this is fixed in later versions of V-ray for Maya, but is it fixed as of version 2.00.01? That’s the version I’m running (I believe it’s the latest one for Maya 2012?),
The rectangular light intensity is being increased when is scaled up.
Are you able to get difference in the render brightens when use exactly the same light size but different scale?