What compelling reason is there to go out of the way to replace all the old dials for any watch that comes in to a service center? It seems to suggest that they want to stamp out any dramatic rise in the price of the old version (due to scarcity value): if you buy an old one for collection purpose you better not wear it bc if it breaks one day you will lose the dial (or lose function of the watch). Not wanting to make any more of the old dials to save cost is not an excuse, it won’t save that much and as I understand it they keep old parts or will make parts to repair all of their old watches anyway.