QTR-Quadtone RIP

I've been using Windows 7, K7 inks in Epson 3880 and QTRgui with no problems

I'm trying to move to a Macbook Pro running Mavericks and am getting very dark (mostly black) prints with the same images and QTR .quad curves.  i.e., on Windows 7 I can print a very nice, smooth step wedge, but on Mac everything is black except for the lightest (10%) values

Everything seems to have installed correctly - I did the 2.7.2 mac install and then installed the Mavericks plugin and also used the Mavericks printer/curve installer files.    I created a Quad3880-K7 printer and have loaded the default curves along with some custom .quad curves that I've had created and have been using with success on Windows 7.   The basic functionality seems to be working, except that the images are just very dark (black, except for the top 10-15% values).   

On Mac, I've tried printing to QTR directly from Photoshop CC and from QTR-Print-Tool with essentially the same results.  I've tried about every permutation of parameters of the various print dialogues with essentially the same results.  I've also tried a couple other .quad curves with similar results.

As an example, I'm using a 8-bit grayscale step wedge image (and also tried an 8-bit sRGB version of the same image)

On QTR-Print-Tool main screen -> Print Color Management
- Application Managed (on Print Tool I've also tried No Color Management and System Management and all possibly permutations from PS CC)
- QTR_Gray_Photo_Paper (in PS, I also tried QTR_RGB_Photo_Paper)
- Relative_Intent (I've also tried Perceptual_Intent and in PS a variety of conversion parameters)

After pressing Print...
- Color Matching = QuadToneTIP (I've also tried ColorSync)
- QuadTone RIP:
- Mode = QuadTone RIP 8-bit
- Curve 1: = (my .quad file, as well as other .quad files)
- Resolution = 2880 dpi (same as I used on Windows 7)
- Speed = Uni-directional (same as I use on Windows 7)
- Black Ink = Photo Ink (same as I use on Windows 7, and the correct setting for IGFS)

I've tried similar variations directly from Photoshop CC, again with very similar results.   I've confirmed that they same .quad file and image file still prints correctly from QTRgui on Windows 7.

Note, I only have K7 inks in my 3880 so I haven't been able to test color printing, but I am able to print color to an Epson R2400 from PS.   The 3880 Maverick-compatible print driver just came out and I installed that, but I'm not sure if that is even used when using Print Tool (or Photoshop) and QTR.

Any help is appreciated.
Tom