Well....Kaedii is red at the moment. I don't think they'd want two shades of red.
I think Because it was necessary to assign a red in the group that's why it gave the red to kaede ! but it's an italian red !!
The normal red is usually attributed to the most popular group except miki ! Only Abe, KUSUMI and Sayashi got it and it was the most popular of every Era ! On Goto maki too.
if i remember Goto's color was orange, and it was an image color so not completely official either.