George Caloz & Frres, located in Grenchen, Switzerland, makes luxury custom watches in small lots. One of the companys products, a platinum diving watch, goes through an etching process. The company has recorded etching costs as follows over the last six weeks: Week Units Total Etching Cost 1 9 $ 21 2 12 25 3 13 30 4 9 20 5 11 25 6 18 34 72 $ 155