A couple of things to remember. First, just because Larian says you need 150 GB free space doesn't mean that the game requires a 150 GB download. The free space to install will include room for temp files, space to uncompress archives, and potentially the drive's working space.
Second. The EA install may also count as a partial preload as it likely contains many of the necessary textures and other files. That could easily save tens of GB on the download.
