In any case in which the probation officer is charged with the duty of collecting amounts payable to the county under this article, upon the verified application of the probation officer the board of supervisors may make an order discharging the probation officer from further accountability for the collection of any such amount in any case as to which the board determines that the amount is too small to justify the cost of collection; that the statute of limitations has run; or that the collection of such amount is improbable for any reason. Such order is authorization for the probation officer to close his books in regard to such item, but such discharge of accountability of the probation officer does not constitute a release of any person from liability for payment of any such amount which is due and owing to the county. The board may request a written opinion from the district attorney or county counsel as to whether any particular amount is too small to justify the cost of collection, whether the statute of limitations has run, or whether collection of any particular item is improbable.