The capitol grounds planning commission shall have general powers to superintend the administration of the capitol building fund, its interest and income fund, and its investments and properties. It may cause any lands now held in such funds to be sold at market value, direct the conversion of any securities now held by such funds to cash, approve expenditures from such funds subject to law and legislative appropriations, and to do all other things necessary to carry out the intent and purposes of this section. The board of university and school lands or its designee, on the commission’s behalf, shall see to the investment and management of the capitol building fund and its interest and income fund and shall account to the commission concerning these funds at the commission’s request.

Provided further, all moneys and other property in the capitol building fund, except as otherwise appropriated, are hereby dedicated and reserved to the exclusive purpose of the construction of an addition to the legislative wing of the state capitol building, and the capitol grounds planning commission shall take necessary steps to accumulate and conserve the money and property in the capitol building fund for such purpose.

The commission may, during any biennium, expend from the interest and income fund of the capitol building fund a sum not to exceed fifty percent of the unencumbered balance on the first day of any biennium, and such amount is hereby appropriated to the capitol grounds planning commission. The expenditure may be made, after consideration of the capitol grounds master plan, for projects or planning but may not exceed two hundred fifty thousand dollars per biennium. The expenditure may only be made upon approval by two-thirds of the total membership of the commission. The expenditure must be made upon a voucher, or vouchers, prepared by the office of management and budget at the direction of the commission.