Here is my experience
Changed plans to share everything at the store and picked up a few iPhones, added the usage controls online at home as per the Verizon store guy at 4.99 per line, 5 lines..... 10 gb share. At the time of the add I had supposedly used 3gb, after set up at a cap of 2gb per line it told me that every line was over the 2gb threshold.... And that every line had used 3 gb......Remember all lines on share and 3 gb out of 10 had been used between all lines 2 seconds before I added usage controls. Waited a few hours to give it time to update and reset anything to make it right. About 4 hours later I checked again, same story. 3 out of 10 used on share data but on data control it had every phone at 3 out of 10 and thus had shut down all data per controls per line even with 7gb left on share. Called verizon and was told that usage controls did not work on shared data, and they removed them. Seems that the program is only seeing the total data and applying it to every line, why does this not surprise me... So far almost everything the guy at the store told me was way off. Yes it was a corp vzw store.