Mike - the offsets are for working with an auto white balance and can change either A or B to warmer or cooler.

Under white you can change the preset in 100 degree increments

Under matrix>phase you can also tweak it more or less magenta or green.

Its actually very fast, flexible and user friendly compared to most cameras. Very few cameras have the adjustment outside of the menus like you seem used to.

I don 't know why people here are so emphatic on telling everyone to grade their shots later. We hired guns don't have that luxury and often the person who does do it has lousy eyes, no time and doesn't care very much.

Maybe because some of us are the hired guns to do the post work and we'd rather not have to back out screwed up, baked in colors... ;)