I get the impression that the bonus to save vs sleep given to someone who recently resisted sleep was to prevent the flee-sleep tactic.

Was it intended to prevent taking advantage of catching someone not paying attention to get two sleep spells off on them whilst they are sleeping naturally? Or even one whilst they are sleeping and another when they wake and are becoming aware of the situation?

At the moment, I get the impression that you can spam sleep on a naturally sleeping target many times, even as a necromancer, before it actually works, simply because your first attempt failed and each one after that is at a penalty. Was it intended to put a penalty in this situation?