They go to extreme with recommending not to use any CYA. They'll tend to have lower CC due to faster oxidation, but at the expense of more nitrogen trichloride which is very volatile and irritating. The immediate rate of disinfection by-product (DBP) production will be higher because of the higher active chlorine level. It would be better to use a small amount of CYA, say 20 ppm, even in indoor pools and have 4 ppm FC and also use supplemental oxidation (UV, ozone, non-chlorine shock, enzymes).