Digital BW, The Print

I have created a 48 level print step file as per

http://bradhinkel.com/Correction%20Curves%20for%20Digital%20Negatives.htm

To test the BO print of my Epson 900 Photo.  I printed
it normally on EEM and was quite pleased with the
results, except between 90%-98% where all levels seem
identical.  My question now is how do I develop an
adjustment curve to open up those levels?  I have read
numerous descriptions of adjustment curves but I guess
I am too dumb to figure it out.  Can someone give me a
set of simple steps to open up those levels.  On the
whole my BO prints have been very nice but I think I
need to open up the deep shadows.  Or am I
misunderstanding this?  Thanks for your help.

Jerry in Houston