The following types and levels of disciplinary actions are to be prescribed in a progressive manner. However, the type and extent of disciplinary action shall be governed by the nature, severity, and effect of the violation; the type and frequency of previous violations; the period of time elapsed since a prior offensive act; and consideration of extenuating circumstances. More severe levels of disciplinary action may be imposed when a lesser action is deemed inadequate or has not achieved the desired results. One or a combination of any of the following disciplinary actions may be imposed. All disciplinary actions shall be in writing, and if more than one action is imposed, they shall be on a single document and imposed at the same time.