Except as provided in subsections (b) and (c) of this section: employees in a class are to be laid off based on seniority points; and the employee in the class with less seniority points shall be laid off before others in the class with higher seniority points. If two or more employees in the same class have an equal number of seniority points, the employee with less points for total State employment shall be laid off first. If two or more employees in the same class have an equal number of seniority points and the same number of points for total State employment, the appointing authority shall: determine which employee to retain by making a written evaluation of the skills, knowledge, or abilities of each employee; and submit the evaluation to the Secretary.