Pittsley v. State Fund [7/31/98] 1998 MTWCC 61A ARM 24.29.720, an administrative rule adopted by DOL to specify employee expenses which are not wages, was by its own terms effective only commencing January 1, 1993. Where sawyer's injury, and the relevant four pay periods preceding injury, occurred before the rule's effective date, the rule's specification that rental value of timber falling equipment not exceeding $22.50 per day could be excluded from wage rate was not applicable to computation of his wage rate.