I turned this on, but even though it's showing an icon for it in the task bar, it's not doing anything. Downloads are going at my WiFi speed and aren't using LTE at all.
I think this is a similar situation to Blocking Mode on the S3. Verizon cut that out, but a shortcut was found to it in a similar way. You could turn it on, and it showed an icon in the status bar, but it never actually worked.