Digital BW, The Print

What's the difference between the UT and UT7 inks for a 2200?  Here's
what I see.  UT7 uses 7 inks and UT uses just 6 with a choice between
Eboni and Photo Black making the 7th ink?  UT7 uses black, 3 grays and
2 cool toners where UT has only one cool toner.  UT can be used with
QTR but not the Roark curves where UT7 can be used with both.  Is that
right?  Are the characteristics of the inks different? 

Thanks,

Tom