UE4.8: How do I produce compressed cooked assets?

I have a project with some rather large but sparse textures (eg, mostly transparent). I’d like them to be compressed when cooked and packaged because otherwise, the space required would be excessive, and load time is a lesser concern.

Using the Project Settings dialog in the Editor, I’ve checked the “Create compressed cooked packages” box in the Packaging section, then I hit the “Cook Content for Windows” item under the File menu.

The resulting cooked assets are plainly not compressed: For instance, one texture which was 281k in the Content folder ends up being 5.4M in Saved/Cooked/WindowsNoEditor after cooking.

Am I missing a step or is this a bug?

I believe that the compressed cooked packages are compressed at the point they are packaged into a .pak file, so you would have to select Package Project to see the benefits of the compression.