The Trane-Ductulator is a useful tool, but it will only calculate the pressure drop for a particular flow in a particular piece of ductwork. It cannot provide load calculations to determine how much air flow is needed in each room based on the air handler unit and the home design. These calculations are necessary, so the Ductulator alone is insufficient to meet the prerequisite. Please see the ACCA example worksheet http://www.acca.org/tech/codes/Manual_D_verification.pdf