I took one of the tests, in the OP. It said that I'm a slow reader, but I have good comprehension, as I got all the questions correct. I'd rather have that result, than the opposite (having poor comprehension).
I read those 700+ page Harry Potter books, in less than 2 days, though----so, I DEFINITELY think it depends-on one's actual interest (read, "obsession" LOL) in the material!
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White female; age 59; diagnosed Aspie.
I use caps for emphasis----I'm NOT angry or shouting. I use caps like others use italics, underline, or bold.
"What we know is a drop; what we don't know, is an ocean." (Sir Isaac Newton)