As an alternative to the warranty coverage described in WAC 468-320-060, a contractor may, for the period beginning on the date of redelivery of the vessel to the state and ending one year after that date, provide a replacement bond in the amount specified for warranty coverage in the bid specifications, increased or decreased by ten percent of the net amount of any change orders. Such replacement bond shall be in the form required in the bid specifications, and shall be delivered to the state as provided in WAC 468-320-090.