Digital BW, The Print

I recently calibrated my monitor and Epson 2100 with Gretag Macbeth's Eye-One 
Photo system.  When I use QTR with Carl's curves my prints are about 1/2 a stop or so 
lighter than on screen.  Is this just the difference in printer production tolerances (ie I 
should really construct my own QTR curves for my own printer as I have done for 
colour work) or something else?  I am assuming that in a well calibrated 
environment I should be getting exactly what I see on screen.  Is the QTR/B&W world 
the same as colour in this regard?

Cheers

Steve