Full support! In military, I use EP, but this isn't the best choice because multiple commands can use EP, and the EP cost and "wait time" (cooldown) aren't necessarily supposed to be the same. I would prefer to use a cooldown time rather than EP though, as it would be a better name (seems cheesy that EP is needed to fire a gun), and would fix some issues with multiple attacks that use differing EP values to manage their "reload times".
Preferably, this would be measured in milliseconds (1/1000 of a second, eg: 1000ms = 1 second, 2500ms = 2.5 seconds) for accuracy and standardization.