The full amount of the difference (whether positive or negative) between the base interest rate forecast in the base case financial model and that applying to the refinancing will accrue to the State.
Most PPP projects since the GFC have a floating rate component in the payment mechanism, effective from the first refinancing, which facilitates the State retaining the risk of movements in base interest rates from the first refinancing. If unhedged, for each interest period during the new financing term, the floating rate component will be a positive number (payable to the private party) or a negative number (payable to the State), depending on which way actual interest rates have moved relative to the interest rate forecast in the base case financial model.