"knocked down from" is correct and usable in written English.
It can be used to express a reduction in the amount of something. For example: "The price of the car was knocked down from $20,000 to $15,000."
Annual growth in the 12 months to September was knocked down from 2.3 per cent to 2.1 per cent by the Office for National Statistics.
Another Buffett brand, Pontoon Boats, offered a motor cruiser knocked down from $70,000 to $53,000 for Berkshire Hathaway shareholders.
We still get an occasional glimpse of the competitive fire, as when LeBron James was knocked down from behind Saturday by Tyson Chandler and Pat Riley leapt out of his seat across the court from the home-team bench.
Pippen, dazed for several minutes after being inadvertently knocked down from behind by his teammate Arvydas Sabonis, hit a 3-pointer with 7.3 seconds left, lifting the Blazers to an 81-79 victory.
I skipped dessert in favor of walnuts I'd knocked down from the tree above me while a foursome at the next table, in full Tyrolean regalia, toasted my efforts with glasses of sturm, the new still-fermenting wine.
Overhead the barn swallows, whose nests she and Methfessel had knocked down from the eaves after the young were launched, could be seen "mating wildly in the air... eager to begin over again".
It was a very forceful knocking down from behind.
"They knocked down shots from the outside," Williams said.
He knocked down five from outside the arc, including the biggest one with 2 minutes 33 seconds remaining after Al Horford threw up a wild shot that missed.
At the age of five, Fraser, running in the road to beg for cigarette cards, was knocked down, and from his injuries he developed meningitis.
To comprehensively assess the functional domain of DLGR2 in the midgut, we next selectively knocked down dlgr2 from the VM of adult animals.
