Issue is, GGG is rate limiting queries to the speed of one per second. What it means is I can't download fast. So every stash tab will take one second to be fetch. If you have hundred of it, then you will have to wait several minutes.
Yes, it's hard coded, not live. They will never be exact, or intended to be. It's just a way to see how your general wealth is.
This tool is mainly to share stash with others, not pricing item.
I'm not concurrencing acquisition or procurement, it's just a small feature I'm using, because, why not :). Of course there are more advanced tools, which are making a better job than this tool.
Just use it and share it! I will never ask for tips, or any kind of donation. No need to send anything.