I believe that the DHF should be a living document. This is due to the fact that many other components of a product may be interlinked. If any part of this product were to change, the DHF should be updated to reflect this. Whether it be a material change, a tolerance adjustment or a simple process parameter update all these are minor (or major!) changes that can drastically change the outcome and documentation of a product. Creating a new DHF to capture a small change in the grand scheme of things is not in line with a forward thinking organization in terms of documentation and quality.