changing the screen brightness adjustment value

Hi,

Pressing the screen brightness keys on my laptop changes the brightness in steps of 10%. Or rather, via a fixed scale of brightness values that are 10% apart.

That's a little crude; 35% turns out to be the perfect setting for me. I can configure that value (with some trial and error) via the power  KCM but if I then use the brightness keys I can only achieve 30% or 40% brighness.

Is there any way to tweak this, or do I have to rebuild some component?

Thanks,
R.