The Commission shall implement a merit system adopted under this subtitle. The merit system includes each employee of the Commission, except: the commissioners; the executive director, secretary–treasurer, and general counsel appointed by the Commission under § 15–109 of this article; the Inspector General; and any temporary term employee of the Office of the Inspector General appointed under § 15–503 of this article; a part–time or temporary employee under Subtitle 2 or Subtitle 5 of this title; in Montgomery County, each position excluded under § 20–204(b) of this article; and in Prince George’s County: the deputy chief of park police as provided in § 17–305 of this article; and each director and deputy director as provided in § 20–204(c) of this article.