Thanks for the additional info - I like nice and predictable - this option was decidedly not available last year when they raised my bill all kinds of ways for adding the hotspot. I may try again. Maybe I'll just try to get the standalone product without tying it to my existing account - which will require some creativity, but where there's a will there's a way.
That said, this article does not bode well for future ZTE Mobleys, which is a bummer - it's a nice device:
When a butterfly flaps its wings in China... Hopefully they can crank out a few more for the US market before they run out of parts and pieces or have to otherwise tweak their supply chain.