Guys cmon it's not that complicated.
You have a role, if you choose to forgo your role to "power-up" then you can do that.
Power-up is NOT a duration, it is a requirement. Sacrifice what you could be doing, to do more later (or add another ability).
Ok, so say I'm a saibaman.
Saibaman; you are mafia.
Role: Sacrifice yourself at night to kill 2 random players.
Powerup: 6 nights. 2 random players becomes 2 random townies.
Wish: (Auto) Do not die when you use your power. Instead stay alive as a vanilla mafia.
This means, that at night I can choose to kill 2 random players. However, if I choose to powerup for 6 nights instead of using my power, then on the 7th night I can kill 2 random townies.
Addiationally, if I manage to get 7 dragonballs by day 4, then on night 4 I will be able to stay alive if I use my power. That is a considerable advantage, methinks, so I say, oh well, I'll just use my power now, kill the 2 random players now, keep myself in the game, and skip the chance that I might get lynched before night 7.
Here's another example with differrent circumstances:
I am Dr.Briefs. Bulma's dad, I am an inventor. I am pro-town
Role: I am an inventor. Each night I target someone. That person will randomly be watched, protected, or killed.
Powerup: 3 nights; I can now decide which ability I want my role to use.
Wish: Revive someone you killed with your role.
Ok, so each night I can use my power at it will randomly watch, protect, or kill them. I like killing roles, but I don't want to kill a townie. However, if I get a wish, then I could just bring them back..unless I kill multiple people....ah screw it, I'm going to forgo my power for three nights, PMing theprof that I am "powering-up" and then on the 4th night, I will be able to target someone and do to them whatever I want to happen (whether it be watch protect or kill them).
OK guys? Not that complicated.