"As per" makes me need "aspirin". It is redundant, as much as any two words can mean the same thing. As such, it is incorrect, grammatically. Like "irregardless", "unthaw" and "I could care less/I couldn't care less", it is a well-used bastardization. Soon it will be in the dictionary, I'm sure (sigh!). Virtually every carpenter refers to "lineal feet", which could be the length of a building, but not the # of feet of framing lumber-thats "linear" feet. Or maybe your feet are passed down from your mother, I don't know.