First off, thank you for making this available as a PDF before releasing it in stores. Give me a chance to fully incorporate it into my campaign before the PCs get their mitts on it! Now to the question.
Under Device Power Stunts, it says...
Power Surge: An emergency overload function built into this
device allows it to deliver a single, massive burst of energy.
Activating this extra requires a half action. Until your next
action, it gains a +2 bonus to the ranks of all its features except
hardness. After this time, it automatically shuts down for 5
rounds due to the strain on its systems.
Does this allow the device's damage to exceed stacking limits? I've been looking for something that would allow a one-shot super blast that drains the heroes power afterwards, and this seems to be it. Thanks.

