(a) In all grievances other than those concerning disciplinary actions, the grievant has the burden of establishing, by a preponderance of the evidence, that the grievance is meritorious.

(b) Where a grievant establishes that an evaluation contained falsely prejudicial material which may have been a substantial factor in an agency action, and the question is presented whether the agency would have taken the same action had the evaluation not contained that material, the burden will shift to the agency to establish, by a preponderance of the evidence, that it would have done so.

(c) Where a grievant establishes that a procedural error occurred which is of such a nature that it may have been a substantial factor in an agency action with respect to the grievant, and the question is presented whether the agency would have taken the same action had the procedural error not occurred, the burden will shift to the agency to establish, by a preponderance of the evidence, that it would have done so.