I'm sure this has been asked before, but here goes:
I'm wondering if there is a way to spceify that a power (or spell, or magic item, etc) can be constructed so that it's powers that cost Endurance can be "scaled" by more or less END being spent.
For example, let's say I have an item that provides X PD of armor and Costs Endurance. What would I do to allow a user to say, pay a certain amount of END to get one level of PD one segment, then increase or decrease th rate of END expendiure the next to increase or decrease the PD provided.