(e) The agency's exercise of discretion was:
1. Outside the range of discretion delegated to the agency by law;
2. Inconsistent with agency rule;
3. Inconsistent with officially stated agency policy or a prior agency practice, if deviation therefrom is not explained by the agency; or
4. Otherwise in violation of a constitutional or statutory provision;
but the court shall not substitute its judgment for that of the agency on an issue of discretion.