here is the usage for today (in MB)

I know it's not instantaneous but I downloaded it like 4 hours ago and usage has usually shown up by then.
I also had these suspicions before when watching premierleaguepass and the usage was lower than what I expected it to be. and also another time when downloading the fifa 14 iphone app which is >1GB and the usage for that day was just over 1GB.
I was just wondering if anyone knew if this was the case (that it is zero rated or similar)