(a) The commission may make either of the following determinations without notice and hearing:
(1) Subject to the limitations of Section 56663, approval or disapproval of a proposal for an annexation, detachment, or reorganization which consists solely of annexations or detachments, or both.
(2) Subject to the limitations of Section 56663, approval or disapproval of the formation of a county service area.
(b) Except for the determinations authorized to be made by subdivision (a), the commission shall not make any determinations upon any proposal, plan of reorganization, or report and recommendation of a reorganization committee until after public hearing by the commission on that proposal, plan of reorganization, or report and recommendation of a reorganization committee.