#1. Has to do with temperature nothing to do with stage of break in. As an engine gets hotter you loose power. From my expierence 200 rpms or so is typical loss... if you are loosing a lot then you need to look at your baffling. The better baffling you have the better your engine will run and often the longer it will last - especially if you are running it too hot.

#2. As your engine breaks in you will see in increase in power as the rings seat and everything loosens up... how much is hard to say.. couple hundred rpms or so