Schools in England are likely to be inspected more often if they are merely "satisfactory", the inspectorate says.
Parents are likely to have less frequent reports on good schools
Successful schools will face even shorter inspections than they do now.
Ofsted said it intended to move to a system more "proportionate to risk". But head teachers' union leader John Dunford said it was ridiculous.
He remarked that the "Office for Pig Weighing" was proposing to weigh the pigs more often - when really what they needed was more sustenance.
Ofsted has already shortened inspections - and they now take place at very short notice - and wants people's views on its latest proposals.
It said schools and inspectors thought the current regime, introduced last September, was proving "very effective".
"It reduces the burden of inspection on schools that are achieving very well in order to continue Ofsted's focus on achieving better value for money by focusing resources on schools where there is underachievement."
School self-evaluation is now central. Ofsted said this was very successful in identifying the strengths and weaknesses within the school and the action it was taking.
Some schools that had yet to be inspected had high achievement, good self-evaluation and a good track record from previous inspections.
"We believe these schools need little inspection and we are proposing to reduce the tariff of inspector days," Ofsted said.
But another "success story" had been the monitoring of schools in "special measures" - judged to be failing and given a deadline to improve, with a follow-up visit a year later.
"Ofsted plans to trial monitoring visits in schools given a notice to improve to see whether this will help schools in this situation make sufficient progress to be judged at least satisfactory when they receive a further inspection a year later."
This is likely to be all the more important under government plans to tighten the deadline given to failing schools.
If they have not improved within one year, they face closure or being taken over.
The consultation adds: "There are a number of schools which, while satisfactory overall, still have pockets of underachievement.
"Ofsted is trialling approaches to monitoring these schools over the next few months."
The Association of School and College Leaders welcomed the lighter burden on successful schools.
But it said more frequent inspections of "satisfactory" schools was "completely unacceptable".
General secretary John Dunford is expected to tackle the issue in his speech to the union's annual conference this weekend.
"Weighing the pig more often does not fatten it," he will say.
"But the Office for Pig Weighing knows nowt about pig fattening, so those who need most sustenance will get most weighing."
What satisfactory schools needed instead as "a more coherent support system to help them improve".
He also made the point that more schools failed their inspections last term because Ofsted had "raised the bar".
His association has already written to MPs protesting about powers in the education bill to encourage local authority inspectors to sack heads who did not turn schools around fast enough.