I have seen this discussion 2-3 years back but was not a potent enough seller to be bothered by this!!
If a seller can offer discount code to buyers that are returning, it will save a lot of time communicating before every custom order. They can just buy the standard gig and use the code to get the prices fixed with them before hand. With more orders coming in, you need every nook and corner to save precious time day in day out-
just a suggestion for the fiverr higher ups