Why would external Storage Location be unavailable in Play Music and Play Movies?

I have a Galaxy Tab S running Android 5.0.2. I also have a 32GB SD card installed. Supposedly I should be able to set Play Music and Play Movies to download to the external card, but those options are not available for some reason. In Play Music Settings, I see the **Storage location** option, but it's set to "Internal (on this device)" and it is disabled (greyed out); tapping does nothing to change it. In Play Movies, there is no option at all in Settings nor when I tap to download a rented or purchased movie. I see plenty of referneces online about people being able to set the storage location for both apps, as of Android 4.4 and above, so I'm confused why I can't get it on my Lollipop 5.0.2 tablet. I've confirmed that I can write to the SD card; I've done so via the Android File Transfer app from my laptop, as well as using the Samsung My File app installed on the tablet. Update: I just noticed that this happens only for *some* of the user profiles on the device. The "owner" profile can set the storage locations to external (SD card) but no other user profile can.