Google Play OBB Downloader

I am trying to get my app to work using the Google Play OBB Downloader.

I have followed the tutorial here: http://labs.exoa.fr/tutorial-unity-4-apk-splitting-google-play-obb/

This worked great for a test project I made starting with fresh projects in both Unity and Google Play.

However, when I try to do the same with my existing app I get failure.

My app is around 250MB, so everytime I want to test something I have to wait for that to upload to Google, and then another hour for it to become "active".

After I press the button from the tutorial in my real app I get the following error message:

 Download failed because you may not have purchased this app

This never happened on the test app I made.

The only thing I can think of that is different, aside from all the content of course, is that in my real app I am using multiple prime31 plugins along with the google plugin. They both seem to want to modify the AndroidManifest.xml file along with main.xml, strings.xml, and styles.xml. I have done my best to manually merge these files.

I don't know where to start with this error. Obviously I didn't purchase the app, it's not live yet. But I AM the developer, and it worked on the test app.

Any suggestions?