Prior to formal submittal of this plan to the state board by the south coast district board, and during the time period specified in subdivision (a) of Section 40463, the south coast district board and the state board shall meet to identify and agree on the portions of the plan which are of prime importance to subsequent state board approval of the plan. The south coast district board and the state board shall work together to resolve any differences concerning these key sections prior to formal submission of the plan to the state board. The south coast district board and the state board shall jointly adopt the procedures by which these plan differences shall be resolved.