Unlimited & More Premium Data Question

I have the Unlimited & More Priemium with 4 lines. I understand that the speed may be reduced after 22gb's of data is used. My question is, is this 22gb's per line/individual or for all 4 phones combined. I had assumed it was per line, but phone rep stated it is total for all lines.

Any help would be appreciated. Looking at adding a new line and switching to the new Elite plan.

Thanks,

John