Product design is not a linear process, with all stages of a product advancing at the same rate. Re-use of past design elements in conjunction with introducing new, loosely specified parts within a modern distributed and collaborative design environment presents a problem in accurately estimating likely quality, cost and delivery metrics. This paper presents a new methodology termed ‘Feature Elasticity‘, which determines the impact of change on a product‘s design in terms of its effect upon the relevant process plan as part of an internet-enabled and knowledge-enriched aggregate process- planning system. The methodology is demonstrated via an example based upon an industrial case study.