QTR-Quadtone RIP

I am having problems getting a curve that doesn't flatten out the 
shadows for my images. I am using Condor BW with an Epson 7600 and UC 
inks with Matte Black.

I created a determined my black ink limit to be 50 and created a 
curve and printed a 21 step gray scale. I read the densities using my 
PrintFix Pro Spectro and loaded the values into an Excel spreadsheet. 
I also loaded two ideal step wedge values, 1.50 and 1.55 to compare 
with my 21 step wedge using line graph I created in Excel. After 
several interations of adjusting the Gamma, Shadow and Highlight, I 
got a curve in Excel that was close to the shape and values of my 
ideal. Then I took the density values from that 21 step wedge and 
entered them into the linearization area of curves creation.

Thinking about how bright I was to master this, I printed some images 
only to find that they are not as distinctive in the shadow areas as 
they appear on my calibrated monitor.

I think my process is valid, but the result are less that I think 
they should be. I would sure appreciate some help on my process and 
or my results.