Digital BW, The Print

I've been using the Epson black cartridge for printing Black Only 
with my 1280.  I thought I'd try a Piezo Portfolio Black cartridge in 
order to gain more print permanence.  Looks fine.  That led me to 
wonder if I could leave the Piezo cartridge in the 1280 and use it, 
with the Epson color cartridge, to print color prints.  I ran off a 
couple of color prints.  They look o.k.  Any comments?  Anyone else 
doing similar?

Norm