Exam Krackers touts the following logic, and I've found it to be fairly accurate:
The mind forces everyone to take (mental) breaks during the VR section. Everyone. No one can plow through the entire 60 minutes without losing focus. So what is important is when you take these breaks. If a break is taken in the middle of a passage (unintentionally of course), then the reader loses track of the main argument/logic and is forced to reread, losing additional time.
Their solution is to control when you take these breaks, so that your mind doesn't force you into taking them in the middle of a passage. To do this, look away from the screen before each passage (even the first one) and forget about the previous passage. Spend about 5 seconds here (stretch, yawn, deep breaths, whatever).