115. EXTRA DUTY - Where soldiers are detailed on some continuos duty or labor for ten days or longer, in the quartermaster, commissary, or some other department, where they are entitled to additional pay, it is called “extra duty.” They are most generally employed in the quartermaster’s department as mechanics, laborers, teamsters, etc., and are under the orders of, and paid by, the department in which they are employed.

116. They are generally excused from all military duty, except Sunday inspections, reviews, and musters but may be required to attend drills when their instruction is not complete.

Customs of Service
August V.Kautz