I'm sure if you check your account
You will find that somewhere during one of your device add on removal sessions your account status was changed
When you added a device after , the data per device plan was eliminated
Like had been said it is 'pooled' data
And the plans I remember where data was separate per device, was each device got 10GB
19GB is not too high for 6 hours of HD video from a streaming service
When I record OTA HD video it is approx 6gb per hour
6 hours would be 36GB of disc space
I'm not sure why the post, was the surprise at the amount of data used
Or the surprise at data pool
You apparently had no problem watching movies
And did not get over billed
