This is a specialist industrial case, but the lesson is useful for any employer with an enterprise agreement. A dispute can start with one employee's entitlement and then expose a broader disagreement about how a clause should work for everyone. The problem is that the legal effect of a Fair Work Commission arbitration depends on the dispute that was actually referred to it.
The Court looked at the dispute-resolution clause, the Form 10, the agreed facts, the arbitration questions and the way the FWC decision had been framed. It accepted that the question of construction could be understood as the issue needed to resolve Mr Ammon's entitlement, not a freestanding ruling binding every employee covered by the agreement.
For employers, the practical point is to define the dispute before the arbitration starts. If the business wants a ruling on one worker only, say that. If the union or employer wants a clause-wide outcome, make sure the steps under the agreement and the FWC documents reflect that wider dispute. Loose wording can create expensive argument about what the decision actually binds.