What is the origin and meaning of the phrase "all day" when used in a commercial kitchen?

I've heard the phrase "all day" used when commanding a kitchen brigade. It's generally used in a phrase like "I need 3 filets .. all day". What does this expression mean in this context? And what is its origin, if known?

According to this site on restaurant phrases, all-day means:

that you are counting particular items on the ticket rail, as in "Yes, chef, there are six chicken saltimbocca all-day, three beef tenderloin all-day," and so on. This counting method is a safeguard against forgetting to fire the requisitioned amount of food, especially when the dining room is full and the rail is lined with greasy slips of white paper. Things do get hectic during the dinner rush, and a basic "all-day" count can save your ass when you are plating food.

There is no etymology I could find on where this phrase comes from, but in non-restaurant English all day has been around since c.1000.