I believe you have one Hyung to many in the Chang-Hon pattern set. There are only 24 Hyungs in Chang-Hon. I don't believe Ko-Dang is one of them.
The original Chang-hon pattern set had only 20 patterns, but later Choi dropped Ko-Dang and added Eui-Am, Moon-Moo, Ju-Che, So-San, and Yon-Gae. Some traditional Taekwondo organizations use Ko-Dang, some replace it with Ju-Che, and some use both.