I think HO quota is there..
Another thing I noticed once that in 1 particular train, there were 20 berths total in the 2A in AB1 coach (there was no wholly 2A coach in that train). After giving 10 cnf berths, railways start issuing tickets in RAC & after 6 RAC, they start giving WL tickets i.e. out of 20, u have given just 13 berths and started WL. This may explain ur RAC getting CNF at charting