He has to sign a Provisional Loadsheet which is used for all calculations. As long as the final ACARs loadsheet is within strict parameters, just an acknowledgement is sent by the crew before take-off on receipt of the final weights.
Maybe you are not familiar with large aeroplane airline operations. 'Discretion' over weights is not used to the same degree, certainly not at 747 level. Any possible discretion is usually in discussion between the Captain and ops staff long before this stage.