Digital BW, The Print

What is the primary drawback of photoblack on matte paper? 
I thought it was Dmax. I used to use ultrasmooth for some prints on my 
2200 but when I see that about $40 worth of ink goes down the drain 
when exchanging carts on the 4800 I lose interest pretty fast. Unless 
I can sell the print for an extra $40 I dont think I'll do too many. I 
have been printing primarily on ceramic luster. It looks like it has 
very good dmax withthe black and white option on the 4800.

charlie