I chose conservatively when I picked the "Advanced Beginner" level. I think I undershot, because I didn't have any trouble with understanding the readings. I also had no problem answering any of the comprehension questions, which are all easy multiple choice answers, and you would need to be entirely lost in order not to get them all correct. I'm used to textbooks and language proficiency tests, which ask cruelly nuanced questions that require total comprehension. This is more like reading for enjoyment, and I would like to try the Intermediate Level just to see if it works better for me.