i just called support and was told that the 5% allowance is for the tier that you come from and not the one that your moving to... that seems kinda messed up to me. i only went over by a small amount 16 texts from s to m. and was charged for 884 texts i didnt use. granted its only 2 dollars but still if it was x to xxl it could add up to a big jump. perhaps you should check into this. by my quick calculation, i went over by 1.7% of the next tier not 5%. i just think it could really upset some customers to see what seems like a bait and switch in your billing.