Child care centers adopting the child care career and wage ladder established pursuant to *RCW
43.215.505 shall increase wages for child care workers who have earned a high school diploma or high school equivalency certificate as provided in RCW
28B.50.536, gain additional years of experience, or accept increasing levels of responsibility in providing child care, in accordance with the child care career and wage ladder. The adoption of a child care career and wage ladder shall not prohibit the provision of wage increases based upon merit. The department shall pay wage increments for child care workers employed by child care centers adopting the child care career and wage ladder established pursuant to *RCW
43.215.505 who earn early childhood education credits or meet relevant requirements in the state training and registry system, in accordance with the child care career and wage ladder.