error in varient price

im getting error in varient configuration.

my main item is cd1

varient color is red, blue, black

im maintaing pr00 for cd1, and va00 for red,blue,black.

cd1 price is RS.500(pr00)and vairents price red RS.10, blueRS.15, bnlack RS.20.

when i raised sales order and im selecting black varient my price should be 520, but im getting 500 only main materil price.

plz give me the suggestions