P800 Change from color to Piezo Pro BW

I am changing a P800 from Epson color inks to the Piezo Pro BW ink set. My nozzle checks print out perfectly (no clogs). Is it recommended to use the Piezo Flush before I switch to BW inks? Will the cost of doing this save me money on the BW inks? Or will I loose just as much BW ink after the piezo flush as I will after the Epson color inks? Is there any other advantage to flushing with Piezo Flush at this point? Thanks.

It saves you from wasting as many as two INITIAL FILLs of Piezograph Pro inks… to rid the stain of the color pigments in the system.