In In re Personal Restraint of Metcalf, 92 Wn. App. 165, 963 P.2d 911 (1998), a challenge was brought to RCW 72.09.480 by an inmate who was incarcerated prior to the passage of the statute. The court held: (1) application of the deductions statute does not violate a prisoner's due process rights; (2) the deductions were not punishment for purposes of ex post facto, double jeopardy, bills of attainder, and excessive fines clauses; (3) the statute did not violate the single subject rule of the Washington Constitution, nor was it impermissible special legislation.