I see this isn't a very active forum...
I don't know much about flower horns, But I've noted with my cichlids that they are capable of VERY rapid color change. My Red devil can go from a pale pink to dark orange within seconds after I walk into the room. My Jack Demsy sometimes has very dull stripes and blue spots, and other times, he has very bold brilliant spots...could be a hunting or defense mechanism...I don't know.