I guess you didn't notice this then. Did you look anything up when I said to show where else it was said?
It looks like it was of interest to the reader in a clearly later time.
1Ch 1:43 These are the kings who reigned in the land of Edom before any king reigned over the people of Israel: Bela the son of Beor, the name of his city being Dinhabah.
1Ch 1:44 Bela died, and Jobab the son of Zerah of Bozrah reigned in his place.
1Ch 1:45 Jobab died, and Husham of the land of the Temanites reigned in his place.
1Ch 1:46 Husham died, and Hadad the son of Bedad, who defeated Midian in the country of Moab, reigned in his place, the name of his city being Avith.
1Ch 1:47 Hadad died, and Samlah of Masrekah reigned in his place.
1Ch 1:48 Samlah died, and Shaul of Rehoboth on the Euphrates reigned in his place.
1Ch 1:49 Shaul died, and Baal-hanan, the son of Achbor, reigned in his place.
1Ch 1:50 Baal-hanan died, and Hadad reigned in his place, the name of his city being Pai; and his wife's name was Mehetabel, the daughter of Matred, the daughter of Mezahab.
1Ch 1:51 And Hadad died. The chiefs of Edom were: chiefs Timna, Alvah, Jetheth,
1Ch 1:52 Oholibamah, Elah, Pinon,
1Ch 1:53 Kenaz, Teman, Mibzar,
1Ch 1:54 Magdiel, and Iram; these are the chiefs of Edom.