Folder values

When moving a card from a folder to "no folder", the value is still showing on the folder in which the card was removed. I have a folder for cards which values are "n/a". When a cards value is added I then remove it from that folder, usually to "no folder", all to easily see when a new price is available when I might otherwise miss it in my almost 7000 cards listed. But the values are remaining in my "n/a" folder. It makes me wonder how accurate the values shown for individual folders are.