(1) The prosecuting attorney, and deputy prosecuting attorneys, of each county with a population of eighteen thousand or more shall serve full time and except as otherwise provided for in this section shall not engage in the private practice of law.
(2) Deputy prosecuting attorneys in a county with a population of from eighteen thousand to less than one hundred twenty-five thousand may serve part time and engage in the private practice of law if the county legislative authority so provides.
(3) Except as provided in subsection (4) of this section, nothing in this section prohibits a prosecuting attorney or deputy prosecuting attorney in any county from:
(a) Performing legal services for himself or herself or his or her immediate family; or
(b) Performing legal services of a charitable nature.
(4) The legal services identified in subsection (3) of this section may not be performed if they would interfere with the duties of a prosecuting attorney, or deputy prosecuting attorney and no services that are performed shall be deemed within the scope of employment of a prosecutor or deputy prosecutor.