As per my understanding, you have two dimension and you want to fix the color for the calculated dimension mentioned in the statement.
Please go to the chart expression, expand the expression and under background color just add below code. Here I have change Downgrade = Red; Opportunity Type = Green;Different Mill = Blue;Ok = Yellow.
Hope this help you.
IF((AllocTransfDestBusinessTp='OPPORTUNIT' and AllocTransfOrigBusinessTp<>'OPPORTUNIT') OR (AllocTransfDestBusinessTp<>'OPPORTUNIT' and AllocTransfOrigBusinessTp='OPPORTUNIT'), RGB(0,255,0),