After the warrant, assessment and diagram are recorded, the same shall be delivered to the contractor, or his agent or assigns, on demand, but not until after the payment to the superintendent of streets of the incidental expenses not previously paid by the contractor, his agent or his assigns, including the amount by which the amount included in the assessment as the cost of any acquisition exceeds the amount previously demanded of the contractor therefor, but with proper credit to the contractor in the event there was included in the assessment as the cost of any acquisition, an amount less than the amount demanded of the contractor therefor at the time of the execution of the
contract pursuant to Section 5256; provided, however, that when the superintendent of streets has, by ordinance, been authorized and directed to receive payments pursuant to Section 5396 of this division said warrant shall not be delivered to said contractor or assigns nor shall such contractor or assigns be entitled to receive payment of assessments by virtue of said warrant within 30 days from the recordation of said warrant.