We will always try to include all the media files accompanying a given month's magazine, however this may not always be possible.
Sadly this is a limitation of the nature of publishing an app, and is highly dependent on how much additional content is produced alongside the magazine each month. In months where we have lots of media to accompany article (such as shoot-outs, or video tutorials), we may not be able to include all of it in the app.
To do so would mean enormous file sizes that would soon fill your Tablet's memory, and would take a long time to download. We have to strike a balance between providing great interactive content and making sure the file sizes are reasonable.
All bonus media content is freely available from the right-hand sidebar of the relevant article, on the Sound On Sound web site (whether you have an account with us or not), so you won't miss out by being a Tablet subscriber.