Hi everyone, there is a lot of misunderstanding about the star rating system.
As others have said, the guest gives and overall star rating separately from the individual category ratings. The overall rating is not an average of the subcategories. Also, the Location rating is not counted towards the Superhost assessment.
In fact, a guest can leave an overall rating and then choose to rate some or none of the individual categories, as that is completely optional. What is more surprising is that, should they not rate some or all of those subcategories, they will show up as 5 stars anyway, under the review that the host sees on their profile page, when in fact they are not 5 star ratings at all! I know that doesn't make sense, but that's how it is. It's a glitch in the system.
Please read my thread here to see a fuller explanation:
https://community.withairbnb.com/t5/Hosting/The-General-Confusion-About-Star-Ratings/m-p/866168#M213...
So, the next time you see that 4 star overall rating with a bunch of 5 star ratings in the subcategories below, do not beat yourself up about it. It is much more likely that the guest didn't rate the subcategories at all (they then show up as 5s by default when they aren't at all in reality).