Same here. I think what's being seen is that some things are easier to diff and update than others. If a game has a large file for map data that's indexed int

Same here. I think what's being seen is that some things are easier to diff and update than others. If a game has a large file for map data that's indexed into, and update to any portions of it are delivered the most easily (where easily includes reliably) by updating the whole file. If that file is 2GB, then you have a 2GB download. If a game has lots of relatively little files, you could update multiple maps with a few tens of megabytes of downloads. An actual patch utility that goes in and applies binary diffs would be much more economical in terms of bandwidth, but then that complicates Steam's ability to confirm a game is in a good state with file checksums, and is much more likely to have odd errors as a diff somehow correctly applies to a file with an incorrect starting starting state.