No wonder I spend so much on propane!
And I think this gets to the heart of it. Why are we trying for such high efficiencies? Going from 75% efficiency to 65% amounts to a pound and a half of base malt in a 5g batch, something like $2. Less than 4 cents a bottle. There is certainly evidence that lower lauter efficiency can give better beer.
I'm guilty as anyone for trying to improve efficiencies, but it's because I enjoy it. It just ain't a problem in the real world.