QTR-Quadtone RIP

I have been using the QTR to get rid of the green color cast when printing on my Epson 
R2400. I have making neutral prints and am no interested in toning them. To that end, I have 
only been using the neutral curve. I am wondering why I normally have to adjust levels by 
about 10-15 points in the negative and also use curves to increase contrast to get my prints 
to look right, when with the Epson driver my prints are pretty close matches to what I see on 
my calibrated seen (albeit with the green color cast). Should I be mixing at least 2 curves, like 
50 cold and 50 warm to get neutral instead?

Thank you.