QTR-Quadtone RIP

I raised this question on the B&W inkjet Group, should do it here as 
well ...

A particular file/image is distinctly sharper with black-only (Epson 
2200 driver) than literal same file/image with QTR (2.3.10), printed 
to the same size.  

Someone on the B&W inkjet group suggested that QTR may *lack* a 
sharpening application that may be hidden in the Epson driver. 

I've never heard of a hidden sharpener in Epson, but they do exist in 
digicams. He suggested I add extra sharpening to a file intended for 
QTR, Vs the file that's already good for black-only.

That helps, though my first efforts make the sharpening obvious in 
close inspection.

** Has anybody else noticed a sharpness issue with QTR Vs Epson? or 
other drivers? 

** Do you use any special sharpening workflow/technique/tool for files 
destined for QTR, as opposed to files destined for other drivers (such 
as Epsons for color or black-only)?