The Commission may initiate a plan or part of a plan with the concurrence of the district council of the county or counties in which the area of the proposed plan is located. The review by the district council of the proposed budget of the Commission and the approval by the district council of the planning schedule that is contained in the budget constitutes concurrence in the initiation of plans proposed in the budget for any single fiscal year. The district council may modify the planning schedule contained in the proposed budget. The district council may direct the Commission to initiate a plan or part of a plan. The Commission shall initiate the plan or part of the plan under subsection (c) of this section with reasonable promptness to the extent funds are available for that purpose.