As per is simply short for as per usual. Given that the phrase is so common in everyday usage, dropping the usual makes it much easier to say and is designed to be used in a non formal manner.
He was drunk last night as per.
With the intended meaning of "according to", this is a popular nonsense phrase used by people trying to sound smart and technical. Since "per" means "according to", the "as" is superfluous.
As per the aforementioned affidavit, I'm a bit of a twat.