Differences between the Host and Remote Control apps

PROBLEM:  Cannot access an Android smartphone when it is in lock mode (sleeping) and has the TeamViewer Remote Control app versus the Host app installed.

OBSERVATIONS: We have noted that an Android mobile device with the TeamViewer Host app installed always appears in the active Mobile section of the TeamViewer interface if the device is ON.  If the device is sleeping, then the entry for the mobile device is dimmed, but can be activated when you attempt to connect to the device.  It apparently wakes up the device.  However, if the TeamViewer Remote Control app is installed, on the remote device then the device only shows in our active Mobile group when the device is NOT in screen lock mode.  Instead, it shows as being offline.

QUESTION:  In order to access a mobile phone when screen lock is ON (sleeping), do we have to install the TeamViewer HOST app?  Which means we will have both the Remote Control app and Host app intalled on some devices.