Digital BW, The Print

I'm mainly hoping Roy and Paul can shed some light on this, but if 
anyone else wants to jump in, please feel free.  I've been looking at 
Roy's very interesting scans of prints, posted in the thread "Dots 
and More Dots". I must admit, I'm slightly surprised by the 
differences. On my monitor, the images measure 4"x4", so that's a 16x 
enlargement factor relative to the physical print. That means that 
viewing the screen from 8ft away is like looking at the print itself 
from 6", which is about as close as I can focus with my naked eye.

What I'm surprised by is the fact that there is such a difference in 
visible dot between the 2200/UT7 print and the 1270/UT2+1160/VM 
prints, especially against the UT2 prints as I thought the inkset 
used a very similar set of grey tones to UT7. If anything, I would've 
expected the 2200 print to be finer due to the smaller drop size, but 
instead the reverse is true. The difference is clear at an effective 
6in viewing distance and still noticeable at 8-12in, so this would 
definitely be a concern to me in a real print. Any idea what gives?

TIA

-= mike =-