Levy of ad valorem tax for payment of general obligation refunding bonds.

In each fiscal year while any general obligation refunding bonds shall be outstanding there shall be levied, by or under the authority of the governing body upon all taxable property in the unit, an ad valorem tax sufficient to pay the interest and principal of such general obligation refunding bonds and any sinking funds which may be provided for by the general obligation refunding bonds or by the proceedings authorizing the sale thereof. However, when there shall be in any fund or funds provided for such general obligation refunding bonds, or any interest or sinking fund, any amount exceeding the amount at that time required for such fund or funds, the ad valorem tax required by this section for the then-current fiscal year may be reduced in the amount of such excess.