I noticed the same thing about rates. I would see different things depending on which web page I looked at. But when it came to using it, I am pretty sure I always got the lowest rates that I saw. It's easy to log in and see all of your calls and texts and see what you got charged. Data is a little tricker, though. It seems like you get lots and lots of data "calls" listed in your account, all with varying charges. Still, for me, I have not run into any billing issues. I used it in the UK, France, and now in the USA. Hopefully, I won't have any problems in the future getting a new USA number and placing a call/text to keep my balance and account going.

My biggest tip is to jot down the APN settings some place handy. They don't always set set automatically when you "latch". And you may need to re-enter them for each NEW country you visit. But AFIK, the settings are always the same for all Toggle countries.