Auckland Grammar School headmaster Tim O'Connor says his school "couldn't operate as we do" without a donation of $1225 a year from parents.
"We do work hand-to-mouth in an operational sense," he says.
"We don't have the capacity to save a lot of money. We don't have the capacity to borrow money - you can only borrow 10 per cent of your operational grant."
He rejects out of hand the Faustian bargain that the new Labour Government is offering schools - an extra $150 a year for every student, probably from next year, on condition that the school stops asking its parents for any donation.
"We couldn't operate, actually, if we accepted that," O' Connor says.
But a Weekend Herald survey sent to all 2531 schools late last year, which drew 544 responses, has found that 70 per cent will accept Labour's deal, and a further 21 per cent are unsure until they see the details of what they will still be allowed to charge for.
Auckland Grammar is in a minority of 8.5 per cent of schools where the parents' donations are so much above $150 per student that they would lose too much by accepting the bargain.
Almost 30 years after state schools became self-governing in the 1989 "Tomorrow's Schools" reform, our survey found that 79 per cent of schools now ask parents for "donations".
In state schools, they range from a just $7 a year at Ngāruawāhia Primary School to Auckland Grammar's $1225.
Only 21 per cent of schools still don't ask their parents for anything. At Sir Edmund Hillary Collegiate in Ōtara, which has 1100 students across junior, middle and senior schools from Years 1 to 13, many parents struggle even to put food on the table.
"All our students are aware that if they don't have breakfast, we will provide it, very discreetly," says senior school principal Peter Uys.
Middle school principal Kallie Ngakuru-Syder says parents will often keep their children at home if they don't have food because they are embarrassed, so the school assures them that it will fill the gap.
"We are part of KidsCan, so we get rain jackets and shoes for students. They provide the breakfast for our students," she says.
Uys says the board tried asking for a donation a few years ago but it was not successful and was abandoned.
The senior school's accounts still show $520 in "donations" and $8224 from "fundraising". But most of this is from pokie trusts.
"I use them a lot," says Ngakuru-Syder. "We did a lot of sun shades, big umbrellas and things, our allocation won't allow for that. All our school trips are paid for through trusts - we have been to Rotorua, we are going to Waitangi this year."
Financial data for all 2472 state and integrated schools, provided by the Ministry of Education in response to a Weekend Herald request under the Official Information Act, shows that average donations in 2016 ranged from $114 per student per year in schools in the poorest areas (decile 1) up to $314 a year in the richest areas (decile 10).
Average total "local" or non-state funding ranged from $522 per student in decile 1 to $864 per student in decile 10.
However, this imbalance was more than compensated by state funding, which averaged $12,068 per student in decile 1 schools and just $8435 per student in decile 10.
State funding rose by 11.1 per cent over the four years 2012 to 2016, a significant real increase in a period when consumer prices rose by only 3.3 per cent and the top of the basic teachers' pay scale rose by 7 per cent.
But schools' income from non-state sources rose even faster, by 13 per cent.
Auckland Grammar, which dropped from decile 10 to decile 9 after the 2013 Census found increased overcrowding in its wealthy catchment area, says its requested donation is calculated to make up for what it loses in state funding.
"The difference in funding that a decile 1A school receives, compared with us, is $930 per student, so before we start getting ahead we are trying to reduce that funding shortfall," O'Connor says.
Grammar asked parents for $950 per student in 2012 and has lifted its request, mostly in $50 annual steps, to $1125 in 2016, $1175 last year and now $1225.
Its accounts show that it actually collected $831 per student in parents' donations in 2016, indicating that parents paid on average 74 per cent of what they were asked for.
However in 2016 it also raised $780,000, or an average of $309 per student, in donations from trusts towards the $4.6 million cost of a new classroom block which the school decided to build itself rather than waiting for state funding.
It has an array of trusts, such as the Auckland Grammar School Foundation Trust and the Headmasters' Council, which reported a combined revenue in 2016 of $1.9m - although O'Connor says none of that went into the school's day-to-day operations.
"The Foundation Trust is an entirely separate entity. We would never draw those lines together in any way," he says.
"The Headmasters' Council is doing things like buying art works. They provide opportunities for staff. They are like a parent-teacher association."
He says the council dates from the days when all Auckland's grammar schools had a single board.
"They might assist if we asked them, very kindly, with a capital project. They supported us with $100,000 towards that funding of $4.6m that we had to fundraise for. But in terms of operations they don't assist us at all."
The school's next-biggest source of operational income, after the state and parents, is international students. Currently 145 students pay international fees which in 2016 totalled $2.7m, contributing $1057 on average towards educating each of the school's 2525 students.
The school spent $875,000 on staff and other costs to recruit and care for its international students, so their net contribution to the school's educational resources was $1.8m, or $710 for every Grammar student.
It made a profit from hostels of $540,000, or $214 per student, and earned a net $666,000, or $264 per student, from "trading" - a category that includes uniforms, stationery, tuck-shop rental and hiring out sportsfields and the theatre.
Trading income also included rents of $289,000 ($114 per student) from 17 houses in Clive Rd acquired a few years ago from the neighbouring Mt Eden Prison and now mainly rented out to teachers as an incentive to work at Grammar.
Nationally, international students in NZ schools have grown strongly from 8936 in 2012 to 11,012 in 2016 and 12,134 last year, although they are still below a 2003 peak of more than 17,000.
Income from those students rose by $36m, contributing the biggest single chunk of state and integrated schools' total $106m increase in non-state revenue from 2012 to 2016.
However, only 551 schools, about a fifth of all state and integrated schools, have international students, and 76 of those have only one student each. The biggest numbers, about 300 each, are at two decile-9 Auckland schools, Macleans College and Westlake Girls' High School.
Sir Edmund Hillary Collegiate, formed in 2004 by merging Hillary College, Bairds Intermediate and Clydemore Primary Schools, has no international students, no hostel, no charitable foundation and very few other sources of income apart from the state.
It contracts out its tuck-shop and uniforms, so its senior school's only "trading" income in 2016 was $21,329 from stationery, about $43 per student.
Parents also paid an average of $115 per student for "activities fees" for things like technology materials and camps. (Auckland Grammar parents paid only slightly more for such things, $136.)
Uys says the school helps parents who can't pay and provides uniforms if families can't afford them.
"In a decile-1 school you can't take things for granted like you can in a decile-10 school. We don't take for granted that students will necessarily have stationery or uniforms. You have to provide it," he says.
Yet while the senior school's total non-state income is not quite $200 per student, one-20th of Grammar's total of almost $4000, its state funding in 2016 was about one-and-a-half times what Grammar gets - $9803 per student, against Grammar's $6291.
Its teacher salaries grant is bigger per student, although the staffing formula for state schools is based purely on student numbers so the difference is due to the Otara school's smaller size, spreading its base teaching allocation across fewer students.
The biggest difference is in the operations grant, which covers most school costs apart from teacher salaries and can be used partly to hire extra teachers. Grammar employs 7.5 teachers above its ministry-funded entitlement, and Sir Edmund Hillary employs an extra three.
The operations grant includes extra funding for lower-decile schools and, since last year, for students judged "at risk" because their parents have been on benefits for 75 per cent of the past five years. Overall, the Otara senior school's operations grant in 2016 was almost $3200 per student, more than double Auckland Grammar's $1500.
The Otara school also gets more per student for English for speakers of other languages (ESOL), special education including the Ongoing Resourcing Scheme (ORS) for students with disabilities, resource teachers of learning and behaviour, and grants for students to attend tertiary courses.
"We have opportunities for students to enter into apprenticeships," Uys says.
"We have huge support from MIT [Manukau Institute of Technology]. They provide scholarships for our students. Four of our students [last year] received substantial scholarships for further studies."
If Auckland Grammar gave up the $831 per student that it received from parents in 2016 and accepted $150 per student from the Government instead, it would lose $681 per student, or $1.7m a year - equivalent to 22 teachers at the current top rate of the basic salary scale ($78,000).
"The consequence of that would be students not being able to take subjects that they wanted to," O'Connor says.
"Some of the languages are low numbers. It would affect our ability to offer te reo, Latin in the senior school. That would be the case for all of those languages, Japanese, and some art-related subjects and some technology-related subjects."
Grammar offers five languages (Maori, Latin, Japanese, French and Spanish), as well as classical studies.
Sir Edmund Hillary Collegiate offers four: Maori, Cook Islands Maori, Samoan and Tongan.
If the Government goes ahead with its proposed $150 per-student grant to replace parent donations, it would give the collegiate's senior school an extra $74,400 a year - enough for one extra teacher.
"We strongly support the Government's policy to eradicate poverty, and education is perhaps the most important tool that could be used to eradicate poverty," Uys says.
"If we get $150 per student it would make a huge contribution to provide better services, better pastoral care and quality teaching to our students."
But Uys, who was rector of a black teachers' training college in South Africa before moving to New Zealand in 1998, is not complaining.
"I don't think we are under pressure so far as funding is concerned," he says.
"We try to manage what we have. You always want more. It would be nice to have extra, but you just can't provide unlimited money.
"I'm coming from a country where this is a luxury. We taught under a tree with no resources. A lot of our staff are coming from war-torn countries - we have two from Iraq. We have refugee students here.
"When I bring visitors here from my country and tell them this is a decile-1 school, they say this is not a poor school. They think this is luxury."