I would like the OP to submit his/her own rendition of the test they are performing. Not the instructions, but perhaps a line by line recap of how the test is performed in their own words.
Something's fishy about the CC test issue. Either the pool has >5ppm CC or the testing protocol is off in some way. Either is plausible, the pool is green and the tester is new to testing. This DPD test is as accurate as they come, and there is little or no reason for it not to work as is reported.
Are you...
using 10ml sample
two dippers of DPD powder
then sample turns hot pink
dropping R-0871 one drop at a time (bottle held vertically, full drops)
Recording when it turns clear
adding R-0003 by 5 drops, swirl
if pink appears...
dropping R-0871 one drop at a time till it turns back to clear???
This protocol is still not working? Or are you still stopping drops of R-0871 at 10 drops? Have you tried 12 drops? 15?
R-0871 isn't so expensive. Order another bottle and then you won't have to worry about using too much. I'd like to see if the CC perhaps is indeed over 5ppm. It'd be a rarity for sure, but I believe it's possible.
Sorry for double questioning it, I just have a lot of faith in the DPD test and the consistent frustration from OP about CC makes me curious as to why it wouldn't work as it's supposed to.