Was there a shorter Route?
A year of two back, there was a lot of talk about Albany WA,(35deg S), being the best departure point for aircraft taking a load down to the Antarctic bases. Had to do with stronger winds from the W/NW as you fly further south. Calculations were an extra 1 tonne on a 737 out of Albany rather than Hobart.
Of course, it was against Albany on the return - better to go Hobart.
Just idly thinking about whether Jon Johanson looked at this aspect, but I have to admit that an extra 10 deg south from Christchurch might more than make up the difference.
THE 'RESCUE'
Further, on the 'rescue' issues, Australia has engaged in several very expensive rescues of yachtspersons, who knowingly sailed far south into known dangerous waters. Bullimore the Pom was one, and the most infamous was the French woman,(twice rescued). Neither of these paid a cent back, despite earning windfall payments from the press and media. The latter was notable for her arrogant lack of contrition.
It begs the question as to whether Jon made any worse a planning decision than these yachties?
cheers,