There's an additional factor to the range of conviction that CE fields have:  stains.  Put simply, every subjective reality leaves a sort of residue of conviction on objective reality.  Previously, I mentioned that beliefs can cause instant distortions, and that fiction made real can return to fiction in the absence of belief.  What I didn't mention was that the loss of reality on a fiction is gradual if there's no belief pushing the transition.
	Consider an isolated village where oranges are believed to be blue.  That village is wiped out by some disaster.  Years later, an expedition group enters the territory of that village and finds blue oranges.  They'll be a bit confused, but likely accept that it's just a weird breed of orange, which updates the fiction while preserving the prior trait of "oranges are blue".  The exact time it would take in isolation for those oranges to become orange again is hard to calculate, but it's a factor of how strongly that village believed it.  The change from blue to orange isn't instant, again, so even just the passage of a month (after the village is wiped out) will result in oranges that are slightly less blue.  Eventually, that "stain" will be gone - as long as no one reinforces it.
	This isn't limited to coherent beliefs.  Strong emotions and memories also leave stains.  Semantic quibbling, I guess - you could say those things hold conviction as well.
	Some settings will have a sort of janitor crew to handle the stains.  It helps stabilize the chaos of how reality works.  Personally, I often put magic monsters in that role because it's a good excuse to bring in alien psychology and to generate easy thematic control.  But not every setting should be like that; some will have other types of natural stain processing - you can think of it like a sort of immune system of objective reality.  And settings that don't have that sort of system will have other things going on because of the stain buildups.  I'm not really here to detail specific settings, though.
	To be clear, even if the stains are instantly wiped clean, it won't amount to much difference if it's immediately influenced to go back the way it was by a CE field.  Like trying to keep your hands dry while swimming, you'll technically have rapid fluctuations, but it's wasted effort that amounts to nothing.
	It's not always as simple as the above example with the oranges, of course.  Since CE fields aren't exactly a real 3d zone, there can be blind spots nearby and focus spots across the world.  The belief could be contrived to be that the blue color indicates ripeness of an orange, or that while non-blue oranges exist elsewhere, the special blue ones have potent medicinal properties.  These beliefs would have less conflict with the stronger beliefs of others about oranges, and allow a better chance of stain combination.  Like trying to mix fluids, you aren't gonna get oil to stabilize together with water - you need to minimize contradictions and there's priority given to older stains.  This is to sort of explain how reality sorts out what can be "true", even though there's no conscious will behind the process.
	Stains always occur at the physical epicenter of a CE field, even if the same stain happens elsewhere.  Example:  belief that the moon is a monster.  The moon itself receives stains (to a degree...), but the believer leaves a stain containing that belief everywhere they go.  Only the direct stain on the moon can directly influence the reality of the moon.  This is important to mention because stains are perceptible via CE fields, even if the individual doesn't understand the data they're getting.  In practice, if that believer is just some crazy vagrant, then if you sleep in a place he slept the night before, you'll probably have a dream about the moon being a monster, or at least be more open to that idea - even if you simply dismiss it as a weird thought.
	I should have mentioned this in an earlier section, but it's hard to stain things that exist in a state of fluctuation.  This is because it depends on how the believer conceptualizes the thing.  Like, let's say a river.  How do you conceptualize that river?  Is it the water flowing through it, the specific space covered by the water, a specific mental snapshot of the river, etc.  All of those allow for different types of staining.  If the river is conceptualized as the water flowing through it, then the river ceases to exist according to the stain if the water flow is cut off.  If the river is conceptualized as the specific space covered by the water, then completely freezing over still allows it to continue existing and if you pick up mud from it it will count as the river being in your hand.  If the river is conceptualized as the specific mental snapshot of the river, then it immediately stops existing except as an echo of the past, because all of that specific water has left the area of the image.