PKG install size question

If updates are replacing the same files over and over, it would make sense that the installers combined are very big but not the resulting files. hdd0 is not compressed.
Have you already ran the game? It didn't install any extra game data to hdd0?

It's more than a few games, actually. I've ran a few of them and yes, it did for two. But the hdd0 folder didn't seem to increase in size, although I didn't notice at the kb level, only GB, so maybe it did install there.