(a) If the terms of the trust instrument do not specify the trustee's compensation, a trustee is entitled to compensation that is reasonable under the circumstances.
(b) If the terms of the trust instrument specify the trustee's compensation, the trustee is entitled to be compensated as specified, but the court may upon petition of the grantor, qualified beneficiary, the trustee or cotrustee, if any, may allow more or less compensation if:
(1) The duties of the trustee are substantially different from those contemplated when the trust was created; or
(2) The compensation specified by the terms of the trust instrument would be unreasonably low or high.