Artifacts size is incorrect?

I’m using the Core 3.1 to build my application with artifacts.
It appears the reported size is incorrect.
for example:

in this run each zip file is reported as 513 mb but when downloading the file the real size is 215 mb.

am I missing something?

I seen somewhere that it is done intentionally, showing size of unzipped artifact. Like, automatic top level archiving is ignored.

When an artifact is downloaded using the GitHub UI, all files that were individually uploaded as part of the artifact get zipped together into a single file. This means that billing is calculated based on the size of the uploaded artifact and not the size of the zip file.

oh I see. Thanks! It is kind of confusing.