Mine is $30 as well, but if you go to the upgrade section online, it discounts $50 from the Razr and Rezound making them $249. I imagine it will do the same for the GN.
And no, the $30 is not based on late payments like someone else mentioned. It is determined by the time of last renewal and the plan contract. In my case it is the primary line of a family plan.
$30 is for feature phones, $50 is for smart phones then $100 is for all those other requirements that somene else posted. Lets drop this subject POOF