Entoman: I have no idea. I just found that no compensation only works for me in low contrast situations. In higher contrast situations a bit of underexposure helps to protect the highlights. I have to admit though that some highlights aren’t worth saving, and that I’m quite partial to deeper shadows.
And, coming back to your point, I can’t imagine that such a small compensation would noticeably reduce noise. But then, after over three years of use, I haven’t even fathomed out how to best use the “step” from 64 to 400 ISO , with this dual gain sensor, let alone how to avoid the dreaded 1/125 shutter speed, which is rumored to cause unsharpness…