Hi Mike,
I have to be honest with you on the asagi. I don't know if the red receeds or not, I have never bred them before and when I studies with kentaro
we dealt with gosanke. my gut instincts is it stays and gets worse. Since you have seen them when they are white with no pattern at the dealers at least you know what we're shooting for! The showa have a brown cast to them but that's because the red plate is over the black. It becomes more evident in two months.