Digital BW, The Print

I've followed Clayton Jones' excellent instructions for black only 
printing on my Epson 2200, including ordering the "ARC-T0348-K" 
cartridge from MIS, and so far the results are stunning. But I'm 
curious as to what ink exactly is in these particular cartridges. 
The MIS web page it appears on says:

"The ink in these carts is the G&G equivalent of Epson's 
Ultrachrome. It is not MIS ink..."

If so, why is it called "Eboni" which MIS uses elsewhere? If it is 
MIS Eboni ink, then what's the difference between this cartridge and 
the UT7 Eboni Black one ("UT7-T0348-UTK")?

Am I missing something obvious?

Morbius