(a) An employee subject to this subtitle shall receive the following written performance appraisals at 6-month intervals based on the employee’s entry-on-duty date:

(1) an informal mid-year performance appraisal; and

(2) an end-of-year performance appraisal with an overall performance rating in accordance with § 7-503 of this subtitle.

(b) An employee’s performance may be rated on a performance appraisal as follows:

(1) outstanding;

(2) satisfactory; or

(3) unsatisfactory.