Downloading directly is the accurate way to state it.
All of our devices (5) download the updates as they become available from the iTunes store, while my local / central iTunes database (running on Windows) doesn't download anything unless I run it and process all outstanding updates.
I've also purchased new apps (over Wi-Fi) from the iTunes store using the device I want it loaded to (first). The other devices can download it from the app store since all purchases are tracked.
I've also started downloading iOS updates over Wi-Fi, since it appears I had some cable and / or security software issues when updating while connected to iTunes (or maybe it was just iTunes itself?). I also turned on Wi-Fi sync (neither of these two points are related to the "five Apple ID issue").
Overall, minimized the need for a local iTunes instance as much as possible.