From my experince with Innodisk, A lot of our customers from Medical sector tent to request a locked bill of materials after the FDA approval. Eventhough simillar components will do the same functionality. but they have different tolerence. non of the componants is accurate 100%. So, they react differently with different systems and can cause a compatitbilty issues. Also, Some project it required to go through FDA approval, which most customer try to avoid to same time if they can. FDA approval can take several monthes and lock BOM is one of the first option customer tent to look for it when it come to very customized solutions.