sorry if I was confusing- yes, you have to use the 25ml sample for the FC test, to get .2ppm results on CC (after completing the FC test)
I think that for most people, getting .2ppm results is probably not necessary- curiosity maybe, or chemgeek when experimenting for science...
But for me, <.5 is good enough on the CC, and my FC stays above 5 normally so not going to use that many drops to get it to .2 accuracy!