Mr Brown is sticking to his guns, saying he sees no need to doubt the study's accuracy. Yet, even setting the dubious assumption on patronage aside, there is good reason to believe he should be rethinking his plan.
KPMG has based its figures on a projection from just six swimming pools. That, in itself, suggests thoroughness has been sacrificed in the interests of the Mayor's wish for quick action.
In the normal course of events, free entry would surely ensure an ongoing boost in usage. And that would mean significantly higher costs to maintain the pools and their facilities. It is also conceivable that the likes of changing sheds and car parks would have to be enlarged, and that more staff would have to be employed.
There seems little prospect that new revenue would balance these operating expenses. In sum, $50 million seems more likely to be closer to the real cost than $5.5 million.
It is, therefore, misleading and somewhat mischievous to have included the latter figure in the city's draft long-term budget. This gives an unrealistic impression, potentially skewing debate on the proposal. If this were, in fact, the cost, few would resent paying for free pools.
The three other options for funding pools in the budget - free entry for children 16 and under at a saving of $450,000, full user charges at a saving of $2.5 million, and the status quo of free entry in Manukau and user-pays elsewhere - would receive little consideration.
Council pools are already heavily subsidised by ratepayers. Each visit to Manukau's six free pools is estimated to cost ratepayers $3.76. Extending that largesse across the city would simply be too expensive, no matter the well-meaning urge to teach children to be safe and confident around water.
To that end, most people outside Manukau seem to find it no obstacle to pay something like $6 for adult entry and $3 for children. Others find it perfectly convenient to use Auckland's many fine beaches to ensure their children learn water safety.
In that context, there seems little reason to extend free pools across the city. Given the uneven distribution of pools and all Aucklanders' easy access to the waters of the Waitemata and the Manukau, a stronger case could be made for instituting full user charges. Better that than an option that ends up costing nothing like what people expected.