The Ranch - Weird Receipt Itemization

Went to The Ranch on West 6th, bought a round of severely under-poured shots (don't get me started) and closed out. She gave me the receipt (http://imgur.com/mIsn7zU) and it was structured like that. I thought they were already including the tip in "Authorized For" so I only included a minor amount. When I looked at my receipt the next day, the "Authorized For" looks to be including tax and not a tip. Why wouldnt they just say tax??