Este hilo del foro necesita una solución

More time used as allowed, without being blocked. Why does it happen?

I received the monthly report, which said that it was used "only" 17 from 30 hours allowed.  When I went to the details, there were: 20 Hours Youtube ( I know my child listen to music here), 20 hrs Whatsapp, 15 hrs Internet searches and even 12 hours Norton Family! The phone was never blocked! 

a) From talking with my child, I understood that if it is selected a Playlist in Youtube and starts playing, when the "Stand-by Function" starts working, it only turns-off the screen (and therefore stops the time of the Norton Family), but it keeps playing the music of that Playlist (which then it can be more than one hour!!)  It happens the same with Spotify. How can this happen? 

b) My other question, why so many hours of Norton Family, where there was clearly nothing done in this time? Does it corresponds to the time for the internet search?

If this cannot be controlled, then I would need another solution for my needs.