In my experience in software patching they actual patch is the smallest part of the process, typically promoting a code set from a content management system.
Other time consuming tasks are Backup, Backup Verification, and QA testing.
With as much data as this game, across all servers, likely must generate. I think a four hour windows is pretty aggressive, even for a small patch.
Just an opinion though, who knows, maybe they are pressing a button to patch and drinking beer the rest of the time! That's the kind of release cycle I could get into!
