Not necessarily. It's not a level field.
Without sales PER-AKL can be had via MEL for $550. Book the same flights separately and it's $277 (inc ~$25GST) and $341 MEL-AKL, a total of $618. Taking the GST into account there's still about a $40 difference.
What happens here is there are different base fares and different taxes depending on route. e.g. There may be a charge for a Dom - Int transfer in MEL that is not applied with separate bookings. These vary between PER-AKL, MEL-AKL and PER-MEL. The base fares and taxes for these routings are currently:
- PER-AKL: $406 & $144 in +++
- PER-MEL: $216 & $ 61 in +++
- MEL-AKL: $224 & $117 in +++
Of course, there is a sale on at the moment and the base MEL-AKL fare drops to $132 & $117 in
+++. (Note the $117 is consistent). So you
could save in this case by doing separate bookings.