The authority granted in RCW 28B.10.300 through 28B.10.330 and 28B.15.220 shall be liberally construed and shall apply to all lands, buildings, and facilities of the nature described in RCW 28B.10.300 heretofore or hereafter acquired, constructed, or installed and to any rentals, contract obligations, bonds or other indebtedness heretofore or hereafter issued or incurred to pay part or all of the cost thereof, and shall include authority to pledge for the amortization plan the net income from any and all existing and future lands, buildings and facilities of the nature described in RCW 28B.10.300 whether or not the same were originally financed hereunder or under predecessor statutes.