Variable. Costing tncome Statement for a Service Company The actuar and planned data for Underwater Unlversity for the Fall term were as follows Theobtration, records, and marketing costs vary by the number of enrolled students. whille instructional costs yary by the number of cent hecirs. Desreciation is a fixed colt. Registeation, reconts, and marketing costa yary by the number of enrolled students, wille instructional casts vary by the number of credt hour. Degredistion is a fixed cost