Within ninety days after the grant funds are fully expended or three years after the grant award date, whichever comes first, the local government shall provide an itemized list of expenditures and written certification that all grant funds were only expended on eligible work plan items. The board may require additional documentation of expenditures prior to closeout. If not all grant funds were expended, the local government shall return unused funds to the board along with the closeout materials. Should the board determine that some funding was not expended on eligible work plan items; the local government shall return such funds to the board within ninety days after receipt of the board's written notice.