According  to Local Govt. Act 51 (6) the deputy mayor may act in the office of the mayor in the absence of the mayor. At the meeting of  9th November 2011 Item 10.2 DEPUTY MAYOR APPOINTMENT, under the “Governance Considerations” the council was advised  that it was good practice to appoint a deputy mayor , “that the burden of duties may be equally shared with the Mayor”.
This advice seems to be a novel creation not justified by the Act. After all, the ratepayers have the right to elect the person they desire to act in the role of mayor as the position is described in the Local Government Act. The advice given would suggest otherwise.

Question
Upon what constitutional or statutory grounds was this advice given  ?