I'm experimenting. I powered down today just see what would happen. And I was told I powered down a specific amount of Vests, that equaled the amount of Steempower I had at that moment. I have since posted and upvoted content and I still am giving out about 4 cents per vote. So I will wait and see if the steem power created from those posts, including this one, will be powered down with the original vests, or left alone.