(a) If the department head or the fire fighter or police officer rejects the proposed solution under Section 143.130, the department head, the department head's designated representative, or the fire fighter or police officer must complete a step IV grievance form and file it with the director within 15 calendar days after the date the person receives the grievance examiner's recommendation.
(b) The commission shall review the grievance examiner's findings and recommendation and consider the transcript of the step III hearing at the commission's next regularly scheduled meeting or as soon as practicable. The transcript shall be filed within 30 days of the step IV grievance being filed. The commission may for good cause shown grant a reasonable delay not to exceed 30 days to file the transcript. In no event may the commission render a decision later than 30 days after the transcript is filed. If the commission does not render a decision within 30 days after the date the transcript is filed, the commission shall sustain the fire fighter's or police officer's grievance.
(c) The commission shall base its decision solely on the transcript and demonstrative evidence offered and accepted at the step III hearing. The commission shall furnish a written copy of the order containing its decision to the fire fighter or police officer, the department head, and the grievance examiner. The copy to the fire fighter or police officer shall be mailed by certified mail, return receipt requested, to the last home address provided by that person. The commission decision is final.