I hope this explains the discrepancy you noticed.
The NHC colours are split similarly to the CHA: standard and non-standard. I understand that the CHA use a mix of their own standards and BHA ones. The exhibition standards are what is found in section C of the NHC handbook (different from Appendx C!).
standard
These have the detailed description found in the handbook, e.g. normal, pearl and sapphire WW, and can be shown in the main class in hamster shows. Getting a standard recognised involves presenting information about its origins (including evidence that it isn't a result of hybridisation), genetics and 3 generations of that colour to the standards committee. Then a provisional standard is used for 2 years when it is reviewed.
non-standard
These colours are recognised as naturally occuring mutations (therefore found in Appendix C) but do not currently have a standard, e.g. merle/marbled WW, opal and platinum campbells. I notice that opal campbells has a CHA standard, which is different to in the UK. They can be shown in the non-standard class which is judged for type etc but not given marks for colour.
Other Colours
There are new colours which have not yet been recognised as mutations, e.g. pied/mottled robo and BEW chinese, therefore they are not listed in Appendix C. I have caused debate among judges by asking whether or not these can still be shown in non-standard and am still none the wiser! Just as well I don't have any BEW Chinese yet to have to worry about it
I find it fascinating to see what happens in shows in other countries. Me and my Chinese hamsters would not do too well at the CHA though!