Martin Marquees makes neon signs to order. Customers can choose from four colors of neon, three letter fonts, and two sizes of signs. Signs typically take one week to make, require between $200 and $300 in materials costs, and can consume from 5 to 10 direct labor hours, and 6 to 14 machine hours, depending on the number of letters and the font. Martin charges customers a 50% markup. Which cost system should Martin use and why?