5The Minister shall ascertain in the case of every elementary education authority in the county the amount of the difference between the actual rate poundage of the authority and the notional rate poundage, and where the notional rate poundage exceeds the actual rate poundage of an authority the difference is hereinafter referred to as the rate disadvantage of that authority, and where the notional rate poundage is less than the actual rate poundage of an authority the difference is hereinafter referred to as the rate advantage of that authority.