Trip swaps between QAL and QCCA are not problematic if the QAL crew members is maintaining or dropping hours in the process but if they are picking up hours then qantas is paying twice because QCCA are on Salary and not hours.
If QCCA drop hours in a trade they still get the same salary if QAL pick it up then Qantas has to pay additional hours that they wouldnt have had to if it remained with a QCCA employee.
Some rules are currently being discussed with management i believe with a view trying to find a solution