But this implies that the second bigger trade was independent of the orders on the books, giving an expectation of a proportional amount of movement. But this i

But this implies that the second bigger trade was independent of the orders on the books, giving an expectation of a proportional amount of movement. But this is very likely to be false. If I'm making a large purchase of an asset with a known value, I'm going to wait for enough volume so that I'm getting a fair deal. The analysis in the article doesn't mention how the order books evolved during the time period analyzed.