Digital BW, The Print

I posted this on photo.net, too, but the chances of an answer are much
better here.

I'm having a devil of a time getting a decent negative out of an Epson
4000.

I make a 101 square "step wedge" as part of my curve building process.
My first negative was on Pictorico OHP film, with the printer set for
Epson Premium Glossy Photo Paper (same way I set the 2200 and the
7600). The step wedge is printer with color management turned off on
the printer driver. I'm getting a density crossover in the darkest
parts of the negative, from 75% to 100%. The curve increases in
density, properly, from 0% to 70% black. At 75%, it levels off, at
80%, density decreases until it's back to the same level it was at
70%, then it begins increaseing from 85% to 100%.

I tried a red negative (this is for multigrade paper, sensitive to
green and blue light, red blocks green and blue) and got a monotonic
increse in density from 0% to 100% (as it should be) but the negative
density range from 0% to 100% isn't enough to get a full DMIN to DMAX
range out of the Ilford multigrade, even at contrast grade 4. I don't
even want to be at 4, the high contrast makes the digital negatives
look "gritty". On the 2200, I have enough contrast range (using more
conventional black negatives, not red) to get a full DMIN to DMAX with
a curve I built for contrast grade 1.5. That's butter smooth, with no
grit.

Anyone have an idea for the next step? Is there another media setting
that eliminates the crossovers (I don't want to make 12 test negatives
and print them all trying to find out).

QTR really isn't an option, the Epson drivers have a dither that makes
a much better digital negative.