Kohler Manufacturing typically achieves one of three production levels in any given year: $8$ million pounds of steel, $10$ million pounds of steel, or $16$ million pounds of steel. In tracking some of its costs, Kohler's controller discovered one cost that was $$10$ per pound at a production level of $8$ million pounds, $$8$ per pound at a production level of $10$ million pounds, and $$5$ per pound at a production level of $16$ million pounds. This is an example of a$\_\_\_\_\_\_\_\_\_$

Kohler Manufacturing typically achieves one of three production levels in any given year: $8$ million pounds of steel, $10$ million pounds of steel, or $16$ million pounds of steel. In tracking some of its costs, Kohler's controller discovered one cost that was $$10$ per pound no matter what the production level for the year. This is an example of a $\_\_\_\_\_\_\_\_\_$