Digital BW, The Print

Someone help me out here....As I understand it, the MIS B&W 
Ultratones for the 2200 do not require any additional software to use 
them -- you simply load a curve into photoshop and print using the 
normal driver.  The B&W Septone inks seem to require additional 
software (the photoshop plug-in or pixelpicasso).

Is this correct?  And if so, I wondering if I should just go with the 
MIS catridges rather than the Septones, since both use 7 shades of 
gray inks for making B&W prints; both have excellent longevity 
ratings; and with the MIS ones, I don't need to pay additional $ for 
software.

Or are there important differences between the 2 systems I'm missing, 
other than the additional software issue?