(a) Compensation and expenses of arbitrators shall be apportioned equally among the parties selecting the arbitrator or, in the case of an arbitrator appointed by the court or selected by agreement of the parties or party-selected arbitrators, shall be apportioned equally among all parties to the proceeding.
     (b) Arbitrators appointed by the court shall be compensated $100 per diem for their service, plus reimbursement for reasonable and necessary expenses. Arbitrators selected by the parties or by party-selected arbitrators may be compensated at a rate not exceeding $100 per diem for their service, and shall be reimbursed for reasonable and necessary expenses.