Pricing based on Actual Ship Date (ADDJ)

Hi All -

I have a situation in which most of business is priced based on Order/Transaction Date (TRDJ).  However, we also need an ability to price based on the Actual Ship Date (ADDJ) for one line of business in the organization.  We will setup "Sales Price Based On Date" constant as Order/Transaction Date (TRDJ) to support the majority of the business.  I am looking for advice to handle the pricing for the section which is priced based on Actual Ship Date. 

Thanks.

CD