I have read on here a couple times to keep adding R0871 during the FC test until you add a drop and get no color change, then subtract that drop. Won't that make your CC result low? It would seem that extra drop of R0871 would hang around unreacted and consume a little CC right when it is formed by the R003 addition. So I would think one could have 0.5 CC and regularly test at 0 instead.