because we "lease" our SteemPower, having our VP at 100% would mean that we are not utilizing the SP as effectively as possible. Some upvotes that could be given to the community is wasted. In a nutshell - as long as VP never makes 100% there is never an idle time where the leased SP is NOT being used. Did that make sense??

To prevent this from happening, it is a very fine juggling act to get the VP high enough to maintain the best return of interest (ROI) , somewhere in the low to mid 90%s is best, and prevent it from reaching 100%.