Despite anything to the contrary in this Part, legal costs that are or have been the subject of a costs dispute under Chapter 5 may not be the subject of a costs assessment under this Division except to the extent that--
(a) the designated local regulatory authority is unable to resolve the costs dispute and has notified the parties of their entitlement to apply for a costs assessment; or
(b) the designated local regulatory authority arranges for a costs assessment under section 284.