Where the Executive Director determines it is necessary or desirable for a project to be performed in separate phases, the Executive Director may negotiate a price for the initial phase work. To establish a contract price for the initial portion of phased work, the Executive Director must first determine that the chosen firm is best qualified to perform the entire project. A contract for work to be performed in phases without a negotiated total contract price must provide that the state may, at its option utilize that firm to perform other phases of the work to be later negotiated and reflected in a subsequent written instrument. The procedures established herein with respect to estimates and negotiation as specified herein shall otherwise apply.