The whole point was that it could have been either aircraft. If it was (as it turned out) the Avalon bound A/C, they had the engineering backup to handle the problem. If it was the Hamilton bound A/C, it would have been stranded on HI, as would the outbound Pax.
I had a similar problem going to HI in a 737. We lost a Generator. No problem, but the aircraft would have been grounded in HI untill an engineer got there (MANY hours!!) to either fix it or apply the MEL. The logical thing was to call into BN and get it done.
I'm no fan of J*, but in this instance it was a normal, rational operational decistion.