If the highway authority, after giving to the nominated undertaker not less than 28 days' notice (or, in case of emergency, such notice as is reasonably practicable) of its intention to do so, incurs any additional expense in the signposting of traffic diversions or the taking of other measures in relation thereto, or in the repair of any highway by reason of the diversion thereto of traffic from a road of a higher standard, in consequence of the construction of the works authorised by this Act, the nominated undertaker shall repay to the highway authority the amount of any such expense reasonably so incurred.

An amount which apart from this sub-paragraph would be payable to the highway authority by virtue of this paragraph in respect of the repair of any highway shall, if the highway fell or would have fallen due for repair as part of the maintenance programme of the highway authority at any time within ten years of the repair being carried out by the nominated undertaker, so as to confer on the highway authority financial benefit (whether by securing the completion of overdue maintenance work for which the highway authority is liable or by deferment of the time for such work in the ordinary course), be reduced by the amount which represents that benefit.