Digital BW, The Print

Hello,
I'm using MIS UTFSn inks with a 1270 printer. While printing on a matte 
papers is ok, I cannot reach a decent DMAX with Glossy Premium (Ebo 
inkset) using the "1270FS-PremSG-Eboni-RGB-PremG" curve: the maximum I 
Dmax reached is 1.24 (x-Rite 800).
I checked curves, workflow, rgb setings, Photoshop settings, epson 
driver without success.
I'm aware the best would be to print with PhotoBlack instead Ebony, but 
I hoped to reach a good dmax without it.
Any experience with this configuration?
Thanks 
Fausto