I think the AQHA and APHA are competent on their color knowledge.
Registry bodies are not known for being either accurate with their colours or up-to-date with current research. Relying on what the registry says can often result in a horse being called the wrong colour.
Just want to add my two cents here. There seems to be a stigma attached to having a horse that is 'just' brown. Almost as if brown is a 'bad' colour. It's not! It's a variation of bay, just like wild bay is. It is not a reflection on your horse's quality, their breeding or their potential. A good horse is never a bad colour, and this applies to our brown equines too.
[SIGPIC]Mel and the AQHA gang , Dualing Lil Highbrow, Light Hershey Kiss, Sugs Sweet Playgirl, Oh Cay With Gunplay, Lena's Smart Ichi Cat, Mia Peppy Freckle