(1) The sheriff shall cause to be kept a record of each and all infractions of the rules and regulations by prisoners, with the names of the persons so offending and the date and character of each offense, and shall examine such records as often as may be necessary to carry out the purpose and intent of this act.

  (2) Every prisoner whose record shows that there are no violations of the rules and regulations shall be entitled to a reduction from his or her sentence as follows: 1 day for each 6 days of the sentence. The sheriff may, by general rule, subject to amendment from time to time, prescribe how much of the good time earned under this subsection a prisoner shall forfeit for any infraction of the general rules and regulations, and for any act of insubordination the sheriff may by special order take away any portion of or the whole of the good time made by any prisoner up to the date of such offense. The sheriff may as a reward for especially good conduct, in case of insubordination, restore to any prisoner the whole or any portion of the good time lost because of any minor infraction of the rules.