The 2012 Electoral Commission review report is worth looking at - http://www.elections.org.nz/sites/default/files/bulk-upload/documents/Final_Report_2012_Review_of_MMP.pdf
page 41, pars 5.6 to 5.8. This does not in any way resolve the technical argument but does suggest flexibility is favoured rather than working to the tyranny of party proportionality determined at the previous general election.