AT&T does something similar - 75% and 90%. I learned the hard way it can't be relied on to be timely! I received a 75% warning on a Friday night from them, con

AT&T does something similar - 75% and 90%. I learned the hard way it can't be relied on to be timely! I received a 75% warning on a Friday night from them, continued to use data (some streaming), and never got the 90% warning, until Monday morning when I received about 20 text messages saying I had used 90%, then 100%, resulting in the automatic purchase of 1 GB more, then 75%, 90%, etc. Even with their credit for the misunderstanding it still cost me > $150 for that lesson.