When you are printing using the ABW driver, you should not be using color profiles such as the Epson-supplied Pro38* profiles. These are designed to be used only for the RGB color driver, not the ABW driver.
For printing using the ABW driver, I recommend making sure your image is in a 2.2 gamma-encoded space (e.g., Gray Gamma 2.2, Adobe RGB) or something pretty close (e.g., sRGB) before printing. Make sure to disable color management in the application (e.g., set Photoshop's Color Handling to No Color Management).
See here for more details:
http://people.csail.mit.edu/ericchan/dp/Ep...w_no_gray_curve