A periodic sum paid to an employee as wages is prima facie an appropriation by the employer to all of the wages due for the period, unless specifically allocated to other obligations.

In reconciling underpayment between an enterprise agreement and a modern award, the shortfall is calculated by reference to what would have been payable under the award consistent with the undertakings, not by mechanical application of award provisions that assume a different ordinary hours structure.

Section 83A(1) requires the Industrial Magistrate's Court to issue an order mandating that the respondent pay to the underpaid employee (not the applicant) the amount by which the employee has been underpaid under an entitlement provision. The use of 'must' denotes an unequivocal and mandatory function with no discretion in either payor or recipient.

While the parties consented to orders for underpaid amounts to be paid to the claimant (industrial inspector), the court's jurisdiction under s83A(1) is mandatory and overrides party consent, as the mandatory nature of the provision takes precedence over the parties' agreement to different terms.

If an employer appropriates a payment to a particular incident of employment, they cannot later reappropriate it to satisfy a different obligation.

The standard of proof is the balance of probabilities, but the seriousness of the allegation and gravity of consequences are considerations affecting whether the issue is proved to the reasonable satisfaction of the tribunal.