Guys
When looking at the graphs remember a few things. They were made by test pilots ( i.e. better than us ) trying to make it as good as possible ! With cleaned and polished blades and a new engine. So they are going to get a better figure than us mere mortals !
Wrong! Performance charts (Hover) are yes made based upon test pilot flights data but the skill to maintain a zero wind hover does not require a test pilot and the engine power at which the charts are made is the minimum spec power i.e. a fully deteriorated engine.