No the middle 50% is a mix of both, only the 25%'s are double bubble for each version.
It could of course be a 50% split, if the mutation occurred on the cut of chem D that mothered them, if only one cut mothered all seeds. That mutation may not exist in another cut, if that was taken from either: a lower part of that plant than the mutation occurred at, or the mother that cut was taken from.
It could of course be a 50% split, if the mutation occurred on the cut of chem D that mothered them, if only one cut mothered all seeds. That mutation may not exist in another cut, if that was taken from either: a lower part of that plant than the mutation occurred at, or the mother that cut was taken from.