E Modifying the cost allocation system for the metropolitan disposal system; providing for metropolitan council determination of the growth cost portion of capital costs for acquisition, construction or rehabilitation of interceptor or treatment works facilities; providing for allocation of the costs among local government units through a fee structure to be charged by the council for new connections to the system; authorizing the council to adopt an implementation plan for transition from the reserve capacity system to the growth cost system, requiring the council to maintain the current service availability charge credit system for recognition of reductions in connections or capacity for local government units with current SAC credit balances choosing to remain on the system (ra, ja)