The 'slightly' option gives the benefit of the the doubt to the superior entity. But if things keep not making sense after further investigation, then the benefit of the doubt is lost. Understanding something, and things making sense are essentially the same thing to me. Things may make sense to someone else, but that means they understand, not me.
If someone designs something or espouses a principle that does not make sense to me, I feel it is my duty to point this out. Even the supposedly brightest minds make mistakes. The process of questioning and explaining is rather important to learning, discovery, and innovation. I believe I am rather capable of changing my mind, and if someone explains something clearly to me, I will understand it.
The "a good amount" option is to be much more earnest in attempting to change ones mind, and gives a lot more time and leeway for the superior entity. Unfortunately, in a lot of scenarios, this much time can be enough for a building to crumble, a bridge to break, a bug to be released, and so on. But I can see how in situations that require a quick response time, how the relative time frames shrink.