I would check the "too good to be true" box for these.
People rarely do things like read, especially under timed conditions, at a pace slower than their fastest.
I took a speed reading course in high school. I can read ~600 words per minute, but my analytical comprehension goes to hell. It works for a novel where you can just hum along & read a story or a magazine article. But if you don't slow down and understand ideas tying together multiple thoughts on the verbal, you won't do well on the questions. In my experience, speed readers can easily tell you what happened in a story, but don't stop to tie in why someone did something or how a character evolved over a novel. I haven't timed myself on how quickly I read the MCAT verbal, but I know for a fact that it's much slower than "speed reading". There's enough time to read the passages - just not much extra.
For the PS section, I tend to be much tighter on time and I have a good PS background so I speed through those passages. But this is just because I know how condensers work and don't need a paragraph giving me vague details about it. If you have time, read in detail - when time gets tight, do what you must.
The only tip that can improve speed and possibly not hurt comprehension is to NOT read out loud - don't say the words in your head. People comfortably hear words being read at about 150 wpm, but you can definitely understand a much faster rate of information. Regardless, you're not going to get over 350 or 400 and truly keep comprehension at 100%, it's just not possible. With passages at 600 words, reading at 600 wpm vs. 300 is going to save you a minute per passage - not very useful compared to comprehension.
