When you have a multiple-item listing (AKA "Dutch" auction) and even when it's just fixed price, you cannot revise many areas including the price if one or more are sold. You would have to close that listing and list again just to revise the price. And it doesn't matter if the auction was automatically re-listed or not.
It's better to be able to adjust your price based on the market demand and conditions. Can we have this ability please?