QTR-Quadtone RIP

Hello, apologies if this message comes through twice, I attempted to 
post it yesterday afternoon but there is no sign of it yet!

I have just started making QTR curves/profiles for my various 
printers.  To start I have made curves for my R220 using the UT-R2 
warm/neutral inksets.  I intend to go on to making curves for my 1270 
using the Cone K6 inksets (Cone don't support this printer).

So far everything looks fine, however I haven't used Black Boost.  I 
cannot seem to find any mention of its use in the various notes that I 
have read on using QTR.  Can someone educate me and tell me when, and 
how, to use this feature please?