A term used by the filthy Rich (aka Kings & Queens) to justify high salary they receive to the sheep followers in order to keep them pacified.
When the richest guy some sheep's know makes a nice handsome salary to match his good looks.
In order to receive such high compensation, one typical assumes the person works more than the average person, hence 13 Hours A Day. But in reality what the person meant to say was 13 Hours A Week.
Prince: "How many hours a day does the King work?"
Queen: "13 Hours A Day, duh!"
Prince: "Oh nice, when can we buy the new Boat?"