Yep I agree with those speed tests data use as well. I was curious to see how fast Public Mobile LTE was?
Download: 90.37 Mbps
Upload: 12.11 Mbps
@DanZap have a look where it shows you the data used. It can add up really quick! Here's a test I did that used the better part of 400MB in one test! I've seen higher from other users, too.